Squash Custard
["1 stick butter or margarine", "5 egg yolks", "1 1/2 c. sugar", "1 qt. evaporated milk (1/2 evaporated milk and 1/2 water)", "1 c. flour", "1 tsp. baking powder (if using plain flour)", "5 squash", "1 tsp. vanilla", "5 stiffly beaten egg whites", "5 Tbsp. sugar"]
["Boil squash until it can be mashed.", "Drain the squash; melt butter in hot squash.", "In a separate bowl, combine egg yolks, 1 1/2 cups sugar, flour and vanilla.", "Stir well and add evaporated milk and water; add to squash and mix well.", "Bake in moderate oven (350\u00b0) until firm, about 1 hour.", "Remove from heat."]
["butter", "egg yolks", "sugar", "milk", "flour", "baking powder", "vanilla", "egg whites", "sugar"]