Preheat oven to 375°F and lightly grease a baking dish.
In a large skillet over medium heat, cook ground beef until browned. Drain excess grease if needed.
Add onion and bell pepper and cook for 4–5 minutes until softened. Stir in garlic and cook for 1 minute.
Stir in sloppy joe sauce, ketchup, Worcestershire sauce, salt, and pepper. Simmer for 5 minutes until thickened.
Transfer sloppy joe mixture into the prepared baking dish.
Sprinkle shredded cheddar cheese evenly over the beef mixture.
Prepare cornbread batter according to package instructions and pour evenly over the casserole.
Bake for 20–25 minutes until cornbread is golden brown and cooked through.
Allow casserole to cool slightly before serving warm.