Preheat oven to 350°F. Combine the onion, crab, water chestnuts, eggs, mayonnaise, salt, pepper, Worcestershire sauce and mix well. Place in baking pan coated with non-stick spray. Top with bread crumbs and margarine or butter slices. Bake on the bottom rack of your oven for 45 minutes.
This warm, comforting casserole can be created as a side to a decadent meal, or as a dip for your favorite chips, crackers or bread!