2 1/2 pounds Ground beef — lean
1 Onion;large — quartered
1 cup Ketchup
1 teaspoon Chili Powder
1 teaspoon Dry mustard
1 teaspoon Salt
2 cups Beef broth — OR water
8 Hamburger rolls — toasted
In skillet, brown ground beef; drain well. Place browned beef and remaining ingredients except hamburger rolls in crock-pot. Cover and cook on LOW setting for 6 to 12 hours. Taste for seasoning before serving. Serve spooned over toasted hamburger buns. 6 to 8 servings