Lemon Layer Cake with Lemon Curd and Lemon Buttercream

Instructions

Cake

1. Preheat oven to 350 degrees F . Grease and flour three 8 inch round baking pans.
2. Mix together the flour, baking powder, and salt. Set aside. 
3. In a large bowl, cream together the butter and sugar until light and fluffy. Beat in the eggs one at a time, then stir in the vanilla. 
4. Beat in the flour mixture alternately with the milk, mixing just until incorporated.
5. 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.
6. Allow to cool in pans on wire racks for 10 minutes. Then invert onto wire racks to cool completely.

Filling

1. In a medium saucepan, mix together 1 tablespoon lemon zest, 1/2 cup lemon juice, and 1 tablespoon cornstarch until smooth.
2. Mix in 6 tablespoons butter and 3/4 cup sugar. Bring mixture to boil over medium heat. Boil for one minute, stirring constantly.
3. In a small bowl, beat egg yolks until smooth. Whisk in a small amount of the hot lemon mixture. Pour the egg mixture into the saucepan, beating the hot lemon mixture rapidly.
4. Reduce heat to low. Cook for 5 minutes or until thick, stir constantly (do not to boil).
5. Pour mixture into medium bowl. Press plastic wrap onto surface to keep skin from forming on the top as it cools.
6. Cool to room temperature then refrigerate 3 hours. 

Frosting

1. In a large bowl, beat confectioners' sugar, 1/2 cup butter, 2 tablespoons lemon juice and 1 teaspoon lemon zest until smooth.
2. Beat in milk, and increase speed and continue to beat until light and fluffy.
3. To assemble:  Place 1 layer on a serving plate. Spread with 1/2 of the lemon filling. Top with another layer, and spread with 1/2 cup lemon filling.
4. Press on final cake layer, and frost top and sides of cake with frosting.
5. Refrigerate cake until serving time.