Ingredients:
Instructions:
Place the bread slices in the bottom of a lightly greased 8-inch square baking dish, then set aside. Saute the onion and mushrooms in butter until tender, then spoon evenly over the bread. Top with the ham. Combine the cheeses and flour together, then sprinkle over the ham. Combine the milk, eggs, mustard and garlic salt and pour over the cheese. Cover and chill for 8 hours. Remove from the refrigerator and let stand at room temperature for 30 minutes. Bake at 375° for 35 minutes or until set. Let stand for 10 minutes before serving. Garnish if desired.