MUELLER'S MUSHROOM TOMATO SAUCE

1 large onion, chopped
1/4 lb. (1/2 cup) butter, divided use
1//2 can (No. 2*) tomatoes
1 (6 oz.) can tomato paste
1/4 lb. mushrooms
1 teaspoon salt
1/4 teaspoon ground black pepper
hot cooked spaghetti (for serving)
grated cheese (for serving)

Fry chopped onion in 1/4 cup butter until brown. Put in saucepan, add tomatoes and let boil 20 minutes.

Add tomato paste and stir.

Fry chopped mushrooms in remaining 1/4 cup butter until brown.

Add mushrooms to tomato mixture with salt and pepper,. Thin to desired consistency with a little water. Let simmer 10 minutes, stirring occasionally.

Serve over spaghetti with grated cheese.

*No. 2 can = 20 oz.

Source:
Recipe Booklet - Magic Menus with Mueller's Macaroni Products, C.F. Mueller Co., 1937