Fancy Broccoli Casserole

1 pkg broccoli, steamed
1 pkg cauliflower, steamed
I can broccoli/cheese soup
I small can mushrooms, drained
1 cup cooked rice
Velveeta cheese
Margarine
Stir in margarine and cheese to cooked rice. Adjust amounts to your taste.
Add soup, undiluted.
Add broccoli, cauliflower, and mushrooms stirring well.
Heat on low on cooktop until cheese melted.