8-10 slices buttered bread, cut into quarters
1 stick butter
1-2 lbs. fresh mushrooms or 2 (8 oz.) cans, drained
1/2 c. celery
1/2 c. bell pepper
1/2 c. onions
1/2 c. mayonnaise
2 eggs
1 1/2 c. milk
1 tsp. dry mustard
1 can cream of mushroom soup
1 lb. Swiss cheese, grated

Saute mushrooms, celery, peppers, and onion in stick of butter. Place layer of bread in casserole dish. Cover the bread with half of the sauteed mixture. Add another layer of bread and remaining mixture. Mix mayonnaise, eggs, milk and dry mustard. Pour over the layers and let stand at least 12 hours. Add mushroom soup and cheese. Bake 1 hour at 350 degrees.