2 boxes frozen broccoli, cooked
1 c. mayonnaise
1 c. sour cream
1 med. onion, chopped
2 c. shredded Cheddar cheese
1 can sliced water chestnuts, drained
1 stick butter, melted
1 1/2 c. Ritz cracker crumbs

Place drained broccoli on bottom of casserole dish. Mix next 3 ingredients and layer over broccoli. Layer with cheese and water chestnuts. Top with crackers mixed with butter. Bake at 350 degrees for 30 minutes.