LEMON CAKE WITH LEMON FILLING AND LEMON BUTTER FROSTING

Steps:

• Preheat oven to 350 degrees F (175 degrees C). Grease and flour two 8 inch round pans. Mix together the flour, baking powder and salt. Set aside.
• In a large bowl, cream together 1/2 cup butter and 1 1/4 cups white sugar until light and fluffy, about 5 minutes. Beat in the eggs one at a time, then stir in the vanilla. Beat in the flour mixture alternately with the milk (1 cup), mixing just until incorporated.
• Pour batter into prepared pans. Bake in the preheated oven for 30 minutes, or until a toothpick inserted into the center of the cake comes out clean. Allow to cool in pans on wire racks for 10 minutes. Then invert onto wire racks to cool completely.
• To make filling: In medium saucepan, mix together 1 tablespoon lemon zest, 1/2 cup lemon juice and 1 tablespoon cornstarch until smooth. Mix in 6 tablespoons butter and 3/4 cup white sugar, and bring mixture to boil over medium heat. Boil for one minute, stirring constantly. In small bowl, with a wire whisk, beat egg yolks until smooth. Whisk in a small amount of the hot lemon mixture. Pour the egg mixture into the sauce pan, beating the hot lemon mixture rapidly. Reduce heat to low; cook, stirring constantly, 5 minutes, or until thick (not to boil).
• Pour mixture into medium bowl. Press plastic wrap onto surface to keep skin from forming as it cools. Cool to room temperature. Refrigerate 3 hours.
• To make frosting: In large bowl, beat confectioners' sugar, 1/2 cup butter (softened), 2 tablespoons lemon juice and 1 teaspoon lemon zest until smooth. Beat in 2 tablespoons milk, and increase speed and continue to beat until light and fluffy.
• With long serrated knife, split each cake layer in half horizontally, making 4 layers. Place 1 layer, cut side up, on a serving plate. Spread with half of the lemon filling. Top with another layer, and spread with 1/2 cup frosting. Add third layer, and spread with remaining half of the lemon filling. Press on final cake layer, and frost top and sides of cake with remaining frosting.
• Refrigerate cake until serving time.