2 lb. ground beef
1 medium onion, chopped
1 tsp. salt
1/4 tsp. pepper
1 (10 oz.) can condensed chicken soup
1/4 cup ketchup (Hunts)
1 tbsp. prepared mustard
8 toasted hamburger buns

In skillet brown ground beef; drain well.

Combine all ingredients except buns in Crock-Pot; stir well. Cover and cook on LOW setting for 6 to 9 hours (or HIGH setting for 2 to 3 hours).

Serve spooned over toasted hamburger buns.

Yield 8 servings (about 2 quarts).