1 lb. ground beef
2/3 c. chopped onion
2 tbsp. oil
1/2 tsp. salt
1/8 tsp. pepper
1 (10 1/2 oz.) can chicken gumbo soup
1/4 c. water
1 tbsp. ketchup
1 tbsp. mustard

Cook meat and onions in oil until onion is golden brown. Stir in remaining ingredients. Cook 30 minutes. Serve on buns.