01 - Heat a large skillet over medium heat. Add the ground beef and cook, breaking it apart with a spatula, until browned and no longer pink, approximately 5 minutes. Drain excess fat if needed.
02 - Add the chopped yellow onion, green bell pepper, and minced garlic to the skillet with the beef. Cook for 3–4 minutes until softened and fragrant.
03 - Pour in the tomato sauce, ketchup, and tomato paste. Add the Worcestershire sauce, brown sugar, yellow mustard, smoked paprika, chili powder, salt, and black pepper. Stir thoroughly to combine all ingredients.
04 - Reduce heat to low and let the mixture simmer uncovered for 10–12 minutes, stirring occasionally, until the sauce reaches your desired consistency.
05 - While the filling simmers, lightly butter the cut sides of the hamburger buns if desired. Toast them in a skillet or under the broiler until golden brown and crispy.
06 - Spoon generous portions of the hot beef mixture onto the bottom halves of the toasted buns. Place the top buns over the filling and serve immediately while warm.