Step 1: Heat the Oven and Prepare the Dish - Start by heating your oven to 375°F. Lightly grease a 9x13 inch baking dish so the creamy filling does not cling stubbornly to the sides later. I like getting the oven and pan ready first because once the beef mixture and biscuit dough are assembled, you can move straight into baking without stopping in the middle of the process.
Step 2: Mix the Savory Beef Filling - Add the browned and well drained ground beef to a large bowl. Stir in the diced yellow onion, minced garlic, kosher salt, black pepper, garlic powder, onion powder, Worcestershire sauce, cream of mushroom soup, beef broth, and frozen peas and carrots. Keep stirring until the creamy mixture coats the beef evenly and the vegetables are distributed throughout. It should look fairly saucy at this point. That is what you want because the filling will thicken as it bakes.
Step 3: Spread the Filling Into the Baking Dish - Spoon the beef mixture into your prepared baking dish and spread it into an even layer. Try to get the vegetables and meat distributed from corner to corner so every serving has a little bit of everything. You do not need to pack the mixture down. Just smooth the surface enough that the biscuit dough will have a nice base to sit on.
Step 4: Mix the Cheddar Bay Biscuit Dough - In a medium bowl, combine the Cheddar Bay Biscuit Mix, cold water, and shredded sharp cheddar cheese. Stir only until you no longer see large pockets of dry biscuit mix and a soft dough forms. This is one place where doing less is actually better. Too much stirring develops the dough more than you want and can leave you with heavier biscuits instead of those soft, fluffy centers we are after.
Step 5: Spoon the Biscuits Over the Beef - Drop spoonfuls of biscuit dough across the top of the beef filling. Leave some small gaps between the portions rather than spreading the dough into one solid blanket. Those open spaces give the biscuits room to bake around the edges and allow steam and bubbling gravy to escape. I also think those little spots where the creamy beef filling peeks through make the finished cobbler look especially inviting.
Step 6: Bake Until Golden and Bubbling - Place the dish in the oven uncovered and bake for 35 to 40 minutes. You are looking for a filling that is bubbling around the edges and biscuits that are golden on top and cooked through in the centers. If the biscuit tops are getting darker than you would like but the middles still need more time, place a loose sheet of foil over the baking dish and let it continue cooking.
Step 7: Make the Garlic Herb Butter - While the cobbler finishes baking, stir the melted unsalted butter together with the garlic herb seasoning packet included in the biscuit mix. Do this close to the end of the baking time so the butter stays warm and easy to brush. The smell alone is usually enough to get somebody wandering into my kitchen asking when dinner will be ready.
Step 8: Brush the Biscuits and Let the Cobbler Rest - Take the baking dish from the oven and immediately brush the warm garlic herb butter generously across the biscuit topping. Get into the little cracks and along the golden edges because that buttery seasoning will soak into the hot biscuits. Then give the cobbler about 10 minutes to rest before serving. That short rest gives the creamy filling a chance to settle and thicken, which means you get hearty spoonfuls instead of gravy running all over the plate.