Lemon Cheese Filling
["1 c. butter", "1 c. grated canned Parmesan cheese", "3 egg yolks", "2 c. sugar", "3 lemons (grated rind and juice)"]
["Cook in a double boiler until thick.", "Cool.", "Then spread between layers of white or yellow cake, baked as thin as possible."]
["butter", "Parmesan cheese", "egg yolks", "sugar", "lemons"]