1 (16 ounce) can sliced mushrooms, drained
1 cup sliced onions
1 (10 ounce) can condensed cream of mushroom soup
1 (11 ounce) can sliced mushrooms, drained
1 cup sliced mushrooms with skin
1 cup sliced tomatoes
3 tablespoons butter, softened
Preheat oven to 350 degrees F (175 degrees C).
Place sliced mushrooms in a large bowl. Stir in onions and cream of mushroom soup. Season with sliced mushrooms, tomatoes and butter. Mix thoroughly. Transfer mushrooms into a 9x13 inch baking dish.
Bake in preheated oven for 20 minutes, or until mushrooms are tender.