Slow Cooker Kung Pao Beef

There are some dinners that just make the whole house smell like you planned better than you actually did, and this Slow Cooker Kung Pao Beef is one of them. I love a recipe like that.

The kind where you spend a little time up front, get the beef browned, whisk together a sauce that smells like your favorite takeout spot, then let the slow cooker do the heavy lifting while you get on with the rest of the day.

This is the meal I make when everybody is hungry, the evening is busy, and I still want something that feels fun. It has tender beef, sweet bell peppers, onion, garlic, ginger, soy sauce, brown sugar, hoisin, and just enough heat to wake everything up.

Then right at the end, in go those roasted peanuts, and suddenly it tastes like something you would happily order on a Friday night.

RELATED RECIPE:Slow Cooker Chicken Fried Rice

Serve this Slow Cooker Kung Pao Beef over a big scoop of warm white rice or a pile of noodles, and you have a cozy, bold, colorful dinner that feels special without being fussy. Around my house, that is the kind of recipe that earns a permanent spot in the rotation.

What Is Slow Cooker Kung Pao Beef

Slow Cooker Kung Pao Beef is a rich, savory, slightly sweet beef dinner inspired by classic kung pao flavors. Thin strips of flank steak or sirloin are seasoned, coated with cornstarch, lightly seared, then cooked low and slow with bell peppers, onion, and a glossy sauce made with soy sauce, beef broth, brown sugar, hoisin sauce, rice vinegar, sesame oil, garlic, ginger, and crushed red pepper flakes.

The slow cooker turns the beef tender while the sauce soaks into every bite. At the end, a simple cornstarch slurry thickens everything into that shiny takeout style sauce we all love.

Roasted peanuts get stirred in before serving for crunch, and green onions and sesame seeds make it look like you really knew what you were doing.

Why You’ll Love This Recipe

• Big takeout flavor: This beef has that sweet, salty, garlicky, savory flavor that makes you want to go back for one more bite.
• Slow cooker easy: Once the beef is seared and the sauce is mixed, the slow cooker handles the rest.
• Family friendly dinner: You can keep the heat mild or bump it up depending on who is sitting at the table.
• Great over rice: The glossy sauce is perfect for spooning over white rice, brown rice, or noodles.
• Colorful and hearty: Bell peppers, onion, tender beef, and peanuts make this meal feel full and satisfying.

When to Serve This Recipe

• Busy weeknights: This is a great dinner when you want something comforting without standing over the stove all night.
• Weekend family meals: It feels a little more special than the usual beef dinner, which makes it nice for Saturday or Sunday.
• Takeout cravings: Make this when you want restaurant style flavor but would rather stay home in comfy pants.
• Meal prep days: The leftovers reheat well, so it is handy for lunches or quick dinners later in the week.
• Casual company: Serve it with rice, noodles, and a simple side, and nobody leaves hungry.

Ingredients

• 2 pounds flank steak or sirloin steak, sliced into thin strips: Flank steak has great flavor, while sirloin stays tender and works beautifully in the slow cooker.
• 1 teaspoon salt: A simple seasoning that helps bring out the beefy flavor.
• 1 teaspoon pepper: Adds a little warmth and balances the sweetness in the sauce.
• 2 tablespoons cornstarch: Coats the beef and helps give the sauce that glossy restaurant style finish.
• 1 tablespoon oil: Helps sear the beef so it gets a little color before slow cooking.
• 1 red bell pepper, chopped into chunks: Adds sweetness, color, and a nice tender bite.
• 1 green bell pepper, chopped into chunks: Brings a slightly sharper pepper flavor that works well with the sauce.
• 1 small onion, chopped into chunks: Cooks down into the sauce and adds a savory base.
• ½ cup low sodium soy sauce: Gives the dish its salty, savory backbone without making it too intense.
• ¼ cup beef broth: Adds richness and helps build enough sauce for serving.
• ¼ cup brown sugar: Sweetens the sauce and helps make it glossy.
• 2 tablespoons hoisin sauce: Adds deep sweet and savory flavor.
• 1 tablespoon rice vinegar: Brightens the sauce so it does not taste too heavy.
• 1 tablespoon sesame oil: Adds that nutty flavor that makes the dish smell amazing.
• 1 tablespoon minced garlic: Fresh garlic gives the best bold flavor.
• 1 teaspoon ground ginger: Adds warm spice and classic takeout style flavor.
• 1 to 2 teaspoons crushed red pepper flakes: Use less for mild heat or more if your crew likes spice.
• 2 tablespoons cornstarch: Thickens the sauce at the end.
• 3 tablespoons water: Mixes with the cornstarch to make a smooth slurry.
• ½ cup roasted peanuts: Adds the classic kung pao crunch.
• Sliced green onions and sesame seeds for garnish, optional: Adds freshness, color, and a pretty finish.

How to Make Slow Cooker Kung Pao Beef

Step 1: Season the Beef

Add the sliced beef to a large bowl, then sprinkle it with the salt and pepper. Use your hands or a sturdy spoon to toss it around until the seasoning is spread over the strips.

I like to do this before anything else because beef needs a little attention right at the start. It is just like teaching kids to tie their shoes.

A little patience early makes everything go smoother later.

Step 2: Coat the Beef with Cornstarch

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Sprinkle the first 2 tablespoons of cornstarch over the seasoned beef and toss until every strip has a light coating. This little step matters more than it looks like it should.

The cornstarch helps the beef brown in the skillet and also helps the finished sauce cling to the meat. You do not want clumps here, just a light dusty coating.

Step 3: Sear the Beef

Heat the oil in a large skillet over medium high heat. Add the beef in batches so the pan does not get crowded.

Let it sear for 1 to 2 minutes, just until lightly browned. You are not cooking it all the way through here.

You are just building flavor. If you pile all the beef in at once, it will steam instead of brown, and we want that little bit of color.

Step 4: Add the Beef to the Slow Cooker

Transfer the seared beef to the slow cooker. Try to scrape in any tasty browned bits from the skillet too, because that is flavor you already paid for.

Spread the beef out a bit so the sauce can work its way around it. This is where dinner starts to feel easy.

Step 5: Add the Vegetables

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Add the red bell pepper, green bell pepper, and onion over the beef. If your family likes softer vegetables, add them now and let them cook the whole time.

If you like your peppers with more bite, add them during the last 1 to 2 hours instead. I usually add them at the start because I like how they melt into the sauce, but both ways work.

Step 6: Whisk the Sauce

In a medium bowl, whisk together the soy sauce, beef broth, brown sugar, hoisin sauce, rice vinegar, sesame oil, minced garlic, ground ginger, and crushed red pepper flakes. Give it a good whisk until the brown sugar starts to dissolve.

This sauce should smell bold, sweet, savory, and a little spicy. That is how you know you are heading in the right direction.

Step 7: Pour and Slow Cook

Pour the sauce evenly over the beef and vegetables. Cover the slow cooker and cook on low for 4 to 6 hours or on high for 2 to 3 hours, until the beef is tender.

I prefer low when I have the time because the beef gets softer and the flavors settle in better. Still, high works just fine when dinner needs to happen sooner.

Step 8: Thicken the Sauce

In a small bowl, whisk the remaining 2 tablespoons cornstarch with 3 tablespoons water until smooth. Stir this slurry into the slow cooker gently so you do not break up the beef too much.

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Cover and cook on high for another 10 to 15 minutes. The sauce will thicken and turn glossy, which is exactly what you want.

Step 9: Finish with Peanuts and Garnish

Stir in the roasted peanuts right before serving so they keep some crunch. Sprinkle with sliced green onions and sesame seeds if you are using them.

Serve warm over white rice or noodles, and make sure to spoon plenty of that sauce over the top. That sauce is the whole point, and nobody should miss out on it.

Substitutions

• Chicken instead of beef: Thin sliced chicken thighs or chicken breast can be used if you want a lighter version.
• Coconut aminos instead of soy sauce: This works well if you need a soy free option, though the flavor will be a little sweeter.
• Cashews instead of peanuts: Cashews give a buttery crunch and are a great swap.
• Yellow or orange bell peppers: These add more sweetness and make the dish even more colorful.
• Fresh ginger instead of ground ginger: Use about 1 tablespoon fresh grated ginger for a brighter flavor.

Variations

• Extra spicy: Add more crushed red pepper flakes or a spoonful of chili garlic sauce.
• Veggie loaded: Add broccoli, snap peas, carrots, or mushrooms during the last part of cooking.
• Sweeter sauce: Add a little extra brown sugar or a drizzle of honey.
• Garlic lover version: Double the garlic for a bolder sauce.
• Takeout bowl: Serve with fried rice, egg rolls, and extra green onions on top.

Tips and Tricks

• Slice the beef thin: Thin strips cook more evenly and turn tender faster.
• Do not skip the sear: Browning the beef adds flavor that the slow cooker cannot create by itself.
• Add vegetables later for crunch: Put peppers and onions in during the last 1 to 2 hours if you want them crisp tender.
• Use fresh garlic when possible: It gives the sauce a stronger, fresher flavor.
• Let the sauce thicken fully: Give the slurry time to work so the sauce becomes shiny and rich.

FAQs

Can I make Slow Cooker Kung Pao Beef less spicy?

Yes, absolutely. Use just 1 teaspoon of crushed red pepper flakes or even less if you are feeding little ones or folks who do not like heat.

You can always add more spice at the table, but once it is in the slow cooker, it is hard to take it back.

What cut of beef works best?

Flank steak and sirloin are both good choices. Flank steak has a nice beefy flavor and slices well, while sirloin is tender and easy to find.

The most important thing is slicing the beef thinly across the grain so it cooks up tender.

Can I skip searing the beef?

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You can, but I would not unless the day is really getting away from you. Searing adds flavor and helps the beef hold up better in the sauce.

If you skip it, the recipe will still work, but it will taste a little less rich.

Can I add the peanuts earlier?

I would wait until the end. If peanuts cook for hours in the slow cooker, they soften and lose that classic crunch.

Stirring them in right before serving gives you the best texture.

What should I serve with this?

White rice is the classic choice because it soaks up the sauce beautifully. Noodles are also great, and fried rice turns it into a bigger takeout style dinner.

Serving Ideas

• White rice: A warm scoop of rice is perfect for catching all that glossy sauce.
• Noodles: Serve the beef over lo mein noodles, rice noodles, or even spaghetti in a pinch.
• Steamed broccoli: The bright green color and simple flavor balance the rich sauce.
• Fried rice: This makes the meal feel like a full takeout night at home.
• Egg rolls: Add a crispy side and dinner feels extra fun.

Storage and Make Ahead Tips

• Refrigerator storage: Store leftovers in an airtight container in the refrigerator for up to 3 days.
• Freezer storage: Freeze in a sealed container for up to 2 months, then thaw overnight in the refrigerator.
• Reheating on the stove: Warm gently in a skillet over medium heat, adding a splash of broth or water if the sauce is too thick.
• Reheating in the microwave: Heat in short bursts and stir between each one so the beef warms evenly.
• Make ahead sauce: Whisk the sauce ingredients together a day ahead and keep it covered in the refrigerator.

Slow Cooker Kung Pao Beef

Slow Cooker Kung Pao Beef is a bold, sweet, savory, and slightly spicy dinner made with tender beef, bell peppers, garlic, soy sauce, brown sugar, hoisin, and roasted peanuts. It is cozy, colorful, and perfect served over rice or noodles.

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Prep Time:20 minutes mins

Cook Time:6 hours hrs

Total Time:6 hours hrs 20 minutes mins

Ingredients

• 2 pounds flank steak or sirloin steak sliced into thin strips
• 1 teaspoon salt
• 1 teaspoon pepper
• 2 tablespoons cornstarch
• 1 tablespoon oil
• 1 red bell pepper chopped into chunks
• 1 green bell pepper chopped into chunks
• 1 small onion chopped into chunks
• ½ cup low sodium soy sauce
• ¼ cup beef broth
• ¼ cup brown sugar
• 2 tablespoons hoisin sauce
• 1 tablespoon rice vinegar
• 1 tablespoon sesame oil
• 1 tablespoon minced garlic
• 1 teaspoon ground ginger
• 1 –2 teaspoons crushed red pepper flakes
• 2 tablespoons cornstarch
• 3 tablespoons water
• ½ cup roasted peanuts
• Sliced green onions and sesame seeds for garnish optional

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Instructions

• Step 1: Season the Beef – Add the sliced beef to a large bowl, then sprinkle it with the salt and pepper. Use your hands or a sturdy spoon to toss it around until the seasoning is spread over the strips. I like to do this before anything else because beef needs a little attention right at the start. It is just like teaching kids to tie their shoes. A little patience early makes everything go smoother later.
• Step 2: Coat the Beef with Cornstarch – Sprinkle the first 2 tablespoons of cornstarch over the seasoned beef and toss until every strip has a light coating. This little step matters more than it looks like it should. The cornstarch helps the beef brown in the skillet and also helps the finished sauce cling to the meat. You do not want clumps here, just a light dusty coating.
• Step 3: Sear the Beef – Heat the oil in a large skillet over medium high heat. Add the beef in batches so the pan does not get crowded. Let it sear for 1 to 2 minutes, just until lightly browned. You are not cooking it all the way through here. You are just building flavor. If you pile all the beef in at once, it will steam instead of brown, and we want that little bit of color.
• Step 4: Add the Beef to the Slow Cooker – Transfer the seared beef to the slow cooker. Try to scrape in any tasty browned bits from the skillet too, because that is flavor you already paid for. Spread the beef out a bit so the sauce can work its way around it. This is where dinner starts to feel easy.
• Step 5: Add the Vegetables – Add the red bell pepper, green bell pepper, and onion over the beef. If your family likes softer vegetables, add them now and let them cook the whole time. If you like your peppers with more bite, add them during the last 1 to 2 hours instead. I usually add them at the start because I like how they melt into the sauce, but both ways work.
• Step 6: Whisk the Sauce – In a medium bowl, whisk together the soy sauce, beef broth, brown sugar, hoisin sauce, rice vinegar, sesame oil, minced garlic, ground ginger, and crushed red pepper flakes. Give it a good whisk until the brown sugar starts to dissolve. This sauce should smell bold, sweet, savory, and a little spicy. That is how you know you are heading in the right direction.
• Step 7: Pour and Slow Cook – Pour the sauce evenly over the beef and vegetables. Cover the slow cooker and cook on low for 4 to 6 hours or on high for 2 to 3 hours, until the beef is tender. I prefer low when I have the time because the beef gets softer and the flavors settle in better. Still, high works just fine when dinner needs to happen sooner.
• Step 8: Thicken the Sauce – In a small bowl, whisk the remaining 2 tablespoons cornstarch with 3 tablespoons water until smooth. Stir this slurry into the slow cooker gently so you do not break up the beef too much. Cover and cook on high for another 10 to 15 minutes. The sauce will thicken and turn glossy, which is exactly what you want.
• Step 9: Finish with Peanuts and Garnish – Stir in the roasted peanuts right before serving so they keep some crunch. Sprinkle with sliced green onions and sesame seeds if you are using them. Serve warm over white rice or noodles, and make sure to spoon plenty of that sauce over the top. That sauce is the whole point, and nobody should miss out on it.

Notes

Substitutions

• Chicken instead of beef: Thin sliced chicken thighs or chicken breast can be used if you want a lighter version.
• Coconut aminos instead of soy sauce: This works well if you need a soy free option, though the flavor will be a little sweeter.
• Cashews instead of peanuts: Cashews give a buttery crunch and are a great swap.
• Yellow or orange bell peppers: These add more sweetness and make the dish even more colorful.
• Fresh ginger instead of ground ginger: Use about 1 tablespoon fresh grated ginger for a brighter flavor.

Variations

• Extra spicy: Add more crushed red pepper flakes or a spoonful of chili garlic sauce.
• Veggie loaded: Add broccoli, snap peas, carrots, or mushrooms during the last part of cooking.
• Sweeter sauce: Add a little extra brown sugar or a drizzle of honey.
• Garlic lover version: Double the garlic for a bolder sauce.
• Takeout bowl: Serve with fried rice, egg rolls, and extra green onions on top.

Tips and Tricks

• Slice the beef thin: Thin strips cook more evenly and turn tender faster.
• Do not skip the sear: Browning the beef adds flavor that the slow cooker cannot create by itself.
• Add vegetables later for crunch: Put peppers and onions in during the last 1 to 2 hours if you want them crisp tender.
• Use fresh garlic when possible: It gives the sauce a stronger, fresher flavor.
• Let the sauce thicken fully: Give the slurry time to work so the sauce becomes shiny and rich.

Serving Ideas

• White rice: A warm scoop of rice is perfect for catching all that glossy sauce.
• Noodles: Serve the beef over lo mein noodles, rice noodles, or even spaghetti in a pinch.
• Steamed broccoli: The bright green color and simple flavor balance the rich sauce.
• Fried rice: This makes the meal feel like a full takeout night at home.
• Egg rolls: Add a crispy side and dinner feels extra fun.

Storage and Make Ahead Tips

• Refrigerator storage: Store leftovers in an airtight container in the refrigerator for up to 3 days.
• Freezer storage: Freeze in a sealed container for up to 2 months, then thaw overnight in the refrigerator.
• Reheating on the stove: Warm gently in a skillet over medium heat, adding a splash of broth or water if the sauce is too thick.
• Reheating in the microwave: Heat in short bursts and stir between each one so the beef warms evenly.
• Make ahead sauce: Whisk the sauce ingredients together a day ahead and keep it covered in the refrigerator.

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Servings: 6 servings

Final Thoughts

This Slow Cooker Kung Pao Beef is one of those recipes that makes dinner feel a little easier and a lot more exciting. It has tender beef, colorful peppers, that sweet and savory sauce, a little heat, and the peanut crunch that makes kung pao so good.

It is simple enough for a weeknight, but it still feels like a treat when you set it on the table.

I love meals like this because they bring everybody into the kitchen before you even call them. The smell does the work for you.

Spoon it over rice, add a few green onions, and enjoy the kind of dinner that tastes like you fussed over it all day, even though the slow cooker did most of the work.