Sloppy Joes

1 pound lean ground beef
1/4 cup chopped onion
1/2 teaspoon garlic powder
1 teaspoon prepared yellow mustard
3/4 cup ketchup
3 teaspoons brown sugar
salt to taste
ground black pepper to taste

In a skillet over medium heat, brown ground beef and onions. Stir in garlic powder, mustard, ketchup, and brown sugar. Stir well. Add salt and pepper to taste. Simmer 30 minutes. Serve on hamburger buns.