In a large skillet over medium heat, brown the ground beef until fully cooked, breaking it apart as you go. Drain any excess fat.

Add the chopped onion and green bell pepper to the skillet. Sauté for about five minutes until softened.

Stir in ketchup, Worcestershire sauce, brown sugar, and mustard until well combined. Allow to simmer for five minutes.

Season with salt and pepper to taste; feel free to add chili or garlic powder for an extra kick.

Spoon the mixture onto hamburger buns and serve immediately, perhaps with cheese on top.