Broccoli Rice Casserole

Ingredients

• 10 ounce pkg frzn minced broccoli
• 1 can cream of mushroom soup
• 1 large onion minced and sauteed in butter
• 1/2 c. grated cheddar or possibly marble cheese
• 3 c. cooked rice
• 1 c. mushrooms (stems & pcs)