1 lb. hamburger meat
1 can mushroom soup
1 tbsp. catsup
1 tbsp. oil
1 onion, chopped
1 tbsp. mustard
1 tbsp. salt

Place oil and chopped onion in heavy skillet over direct heat. Stir until tender, then add hamburger. Separate and mix with onion. Cover and cook until meat changes color, about 10 minutes. Add other ingredients and cook 10 minutes more. Spoon over warm buns.