Sour Cream Filling

• 1 egg yolk
• 2 tablespoons sugar
• 1 tablespoon cornstarch
• 1 cup thick sour cream
• 1/2 teaspoon lemon or vanilla extract

Beat yolk slightly, add sugar and cornstarch, mixed, stir in cream; cook in double boiler until mixture coats the spoon. Add flavoring. If desired, add 1 cup chopped nuts.