Sybil's Old Fashioned Lemon Layer Cake

Step 1
Preheat oven to 350 degrees F (175 degrees C). Grease and flour 3 9-inch cake pans. In a bowl, whisk together 3 1/4 cups of flour, baking powder, and salt.

Step 2
Cream 1 cup plus 2 tablespoons softened butter in a large bowl with an electric mixer until smooth, then mix in 2 1/4 cups of sugar until thoroughly blended and fluffy. Beat 6 egg yolks into the butter mixture, one at a time, beating well after each yolk is added. Beat the flour mixture into the butter mixture in thirds, alternating with milk. Mix in 3/4 teaspoon of grated lemon peel and 1 3/4 teaspoon of lemon juice.

Step 3
With clean beaters, beat the egg whites to stiff peaks in a bowl; lightly fold the egg whites into the batter; use a rubber spatula or wire whisk to fold 1/3 of the beaten egg whites into the batter. Gently run the spatula through the center of the bowl, then around the sides of the bowl, repeating until fully incorporated. Add the remaining egg whites, folding just until incorporated.. Pour the batter into the 3 prepared cake pans.

Step 4
Bake in the preheated oven until a toothpick inserted into the center of a cake comes out clean, 25 to 30 minutes. Allow cakes to cool in pans for 10 minutes; then turn out onto a rack to finish cooling.

Step 5
To make filling, whisk 2 1/4 cup sugar, 2 tablespoons of grated lemon peel, 1/2 cup of lemon juice, 5 1/2 tablespoons of flour, and beaten egg together in a saucepan. Cook the mixture over low heat, whisking constantly, until the filling almost comes to a boil; cook until thickened and smooth, about 1 minute. Whisk in 2 tablespoons of butter until melted. Allow the filling to cool.

Step 6
To assemble, place each cake layer down on a work surface, and place one hand lightly on the top of the cake. Use a serrated knife to slice the cake in half horizontally, with a light sawing motion, to create 2 layers from each cake (6 total layers). Brush crumbs from the layers. Place a cake layer onto a serving dish, and spread with 1/6 of the filling; repeat with all the layers and filling, ending with a layer of lemon filling for the top of the cake.