Lemon Sponge Pie
["1 c. sugar", "3 Tbsp. butter, melted", "yolks of 2 eggs (save whites)", "1 lemon", "3 Tbsp. flour", "1 c. milk"]
["Mix together the sugar, butter and 2 egg yolks, beating well. Add to this mixture the juice and rind of 1 lemon.", "Then add the flour, milk and the 2 egg whites, stiffly beaten.", "Pour in a cooked pie crust and bake 45 minutes in slow oven at 300\u00b0."]
["sugar", "butter", "lemon", "flour", "milk"]