1 (16 oz.) pkg. frozen peas, cooked until almost done
1 sm. onion, chopped
1 (4 oz.) can sliced water chestnuts
1 can cream celery soup
1 c. shredded cheddar cheese
1/2 c. melted butter
2 c. crushed Pepperidge Farm dressing

Mix first 4 ingredients. Pour into a 2-quart casserole. Top with cheese. Mix butter into crumbs. Sprinkle on top; bake at 325 degrees for 30 minutes.