Rice With Mushrooms Rice With Mushrooms Advocate story Sept. 04, 2013 Comments Rice With Mushrooms Serves about 6. Recipe is by Sue Ferachi. 1 cup long-grain rice 1 (10 3/4-oz.) can onion soup Water 2 tbls. vegetable oil 1 (8-oz.) pkg. sliced mushrooms Salt and pepper, to taste 1. Put rice, onion soup and water measured in empty soup can in a covered casserole dish. 2. Add the oil, mushrooms and seasonings. 3. Cover and bake at 350 degrees for 45 minutes or until rice is cooked.