Easy Broccoli Rice Casserole
["1/3 c. plus 1 Tbsp. butter/margarine", "1/2 c. onion, chopped", "1 (20 oz.) bag frozen chopped broccoli", "2 c. cooked rice", "1 can cream of mushroom soup (undiluted)", "1 c. grated Cheddar cheese"]
["You will need a large casserole dish, lightly greased, and aluminum foil."]
["butter", "onion", "broccoli", "rice", "cream of mushroom soup", "Cheddar cheese"]