Brown the Ground Beef
In a large skillet over medium heat, cook the ground beef until evenly browned. Break it into fine crumbles with a wooden spoon or masher for a smoother texture.
Cook the Vegetables
Add the chopped celery and onion to the skillet. Cover and cook for about 5 minutes, or until the vegetables are softened.
Drain excess grease from the skillet to keep the filling light.
Combine Ingredients
Stir in the tomato soup, ketchup, brown sugar, white vinegar, Worcestershire sauce, salt, and garlic powder. Mix well to combine.
Simmer the Mixture
Reduce heat to low and let the mixture simmer for 10-15 minutes, stirring occasionally to ensure the flavors meld and the sauce thickens.
Assemble and Serve
Spoon the filling onto toasted hamburger buns and serve immediately. Pair with your favorite sides for a complete meal.