Sloppy Joes

1 lb hamburger
1 small onion, diced

Brown together

1 c. catsup
1 t mustard (optional)
1 T vinegar
1 T sugar
1/2 t salt
1/8 t pepper
1 c water

Add ingredients to browned and drained hamburger. Simmer 20 minutes. Serve on hamburger buns.