This is an easy to make from scratch sloppy Joe recipe.
Sauté Onion and Garlic in butter. Add ground beef and fry until almost done. Add Bell Peppers and continue cooking until beef is done. Combine ketchup, mustard, chili powder, salt, and pepper in a small bowl, add to ground beef in pan. Stir in diced tomato. Cover and reduce heat to simmer. Cook for about 15 minutes to allow flavors to infuse. Serve hot on buns.