Preheat oven to 400°F. Grease a 9×13-inch baking dish.
Warm olive oil in a large skillet over medium heat. Add onion and bell pepper; cook until softened, about 4 minutes.
Stir in garlic and cook 30 seconds. Add ground beef; brown, breaking it up, 5–7 minutes. Drain excess fat.
Blend in barbecue sauce, tomato paste, Worcestershire, paprika, chili powder, salt, and black pepper. Simmer 3 minutes.
Fold in corn and jalapeño if using. Taste and adjust seasoning.
Spread beef mixture in the baking dish. Sprinkle cheddar evenly over the top.
In a bowl, whisk cornbread mix, milk, and melted butter just until combined. Do not overmix.
Pour batter over the cheese and smooth to the edges. Bake 25–30 minutes until golden and set.
Let rest 10 minutes before slicing so the layers hold together.