Step 1: Brown the beef and onion - Start by heating a skillet over medium heat. Add the ground beef and diced onion, cooking until the beef is fully browned and the onion is soft. This step builds flavor right from the start. Once done, drain off any excess grease.
Step 2: Transfer to the slow cooker - Spoon the cooked beef and onion mixture into your slow cooker. This is where everything will come together and slowly develop that rich, comforting flavor.
Step 3: Add the sauce ingredients - Pour in the ketchup, brown sugar, Worcestershire sauce, yellow mustard, and beef broth. Sprinkle in the salt, pepper, and garlic powder. Give everything a good stir so the meat is evenly coated in the sauce.
Step 4: Let it cook low and slow - Cover the slow cooker and set it to low for about 3 hours. During this time, the flavors will deepen and blend together into that classic sloppy joe taste.
Step 5: Stir in the cooked pasta - Once the sauce has had time to develop, stir in the cooked rotini pasta. Make sure the pasta is evenly coated so every bite is full of flavor.
Step 6: Add the cheese - Sprinkle in the shredded cheddar cheese and stir until it melts completely into the dish. This is where everything turns creamy and comforting.
Step 7: Let it rest - Allow the pasta to sit for about 5 to 10 minutes. The sauce will thicken slightly, and everything will settle into the perfect consistency.
Step 8: Serve and enjoy - Scoop into bowls and, if you like, top with a little extra cheese or fresh parsley for a pop of color.