1Combine the ground beef and onion in a cold skillet, place the skillet onto a stove burner, and turn the heat to medium; cook and stir until the beef is crumbly and browned. Stir the garlic and bell pepper into the beef mixture; continue cooking and stirring until the vegetables are tender, 2 to 3 more minutes. Add 1 cup of water. Mix in ketchup, brown sugar, Dijon mustard, Worcestershire, salt, and pepper. Pour in 1 more cup of water. Bring to a simmer. Reduce heat to low and cook until the mixture becomes very thick, 30 to 45 minutes. Adjust salt and pepper as needed. Season with cayenne.
Aluminum foil helps keep food moist, ensures it cooks evenly, keeps leftovers fresh, and makes clean-up easy.