1/4 c. butter
1 lb. mushrooms, trimmed, sliced (about 6 c. sliced)
1/2 c. chopped celery (with leaves)
1/4 c. finely chopped onion
3/4 c. milk
1 can (10 3/4 oz.) condensed cream of mushroom soup
3 c. soft bread cubes
4 oz. shredded sharp cheddar cheese (about 1 c.)
1 can (6 oz.) water chestnuts, drained, sliced
1/2 c. mayonnaise or salad dressing
1/2 tsp. salt
1/4 tsp. pepper
3 eggs, separated

1. Melt butter in large skillet; cook and stir mushrooms, celery and onion until tender, about 5 minutes.

2. Heat milk, soup and bread cubes just to boiling in large saucepan, stirring frequently. Reduce heat; add cheese. Cook and stir over low heat until cheese is melted. Remove from heat.

3. Heat oven to 325 degrees. Stir water chestnuts, mayonnaise, salt, pepper, egg yolks and mushroom-butter mixture into soup mixture. Beat egg whites until stiff but not dry. Stir about 1/4 of the egg whites into mushroom- soup mixture; gently fold back into remaining egg whites. Pour carefully into ungreased 11 x 7 x 1 1/2 inch baking dish. Bake until knife inserted in center comes out clean, about 1 hour. Makes 4 main dish servings.