This cake with custard filling is a light and tender white cake, filled with a lemon custard filling and topped with a simple whipped cream frosting. You can garnish with chocolate if you have it around, but no need for it to look and taste great.
Separate your egg whites and egg yolks into separate bowls. Keep 3 egg yolks which will be used in the custard. The remaining egg yolks can be discarded or saved for a stir fry, pasta or omelet in an airtight container in the fridge.
With an electric mixer, whip the egg white on medium until foaming. Add cream of tartar.
Add sugar slowly while beating and beat until the eggs and shiny stiff peaks. Set aside.
In a new bowl beat shortening until creamy with electric mixer. Add sugar and continue to beat for 2 minutes.
Add sour cream, vanilla and baking powder and beat for another minute.
In a small bowl mix cornstarch and flour.
To the shortening mix alternate adding cornstarch and milk until all combined.
With a spatula, gently fold in egg whites until entirely combined.
Line 2 - 9 inch pans with parchment and then grease with butter.
Pour 1/3 of the batter into 1 pan, and 2/3 of the batter into the other pan.
Preheat oven to 300 degress F and bake for 20-40 minutes until a toothpick in the center comes out clean.
NOTE: the thin cake will cook much quicker than the thick cake so be sure to check it around 20 minutes.
Slice around sides with a knife to unstick sides- then let cool for 5-10 minutes in the pan before flipping out onto a wire rack to cool. Cool completely before cutting or frosting.
Only the thicker cake will be cut horizontally to make 2 layers.
In a medium saucepan, whisk together sugar and conrstarch. Add milk. Then add yolks, salt, and zest (saving the juice for later).
Cook over medium heat, stirring constantly with a whisk, until thickened.
Remove from heat and stir in lemon juice.
Pour custard through a strainer into a bowl. Cover with plastic wrap so that the plastic directly touches the surface (to prevent a skin from forming on the top).
Refrigerate until cool and ready to use.
Whipped Cream Frosting
In a large chilled bowl, whip whipping cream until it just begins to thicken and become foamy.
Add vanilla and sugar and whip until the consistency of a thick cream.
Place 1 cake layer onto a serving plate. Top with 1/2 the custard, and optionally (drizzle with some chocolate sauce).
Top with 2nd cake layer, followed by more custard and chocolate sauce.
Add the final cake layer and top with frosting, using an offset spatula to make smooth.
Garnish with you choice of shredded coconut and chocolate drizzle or frosting (if you have it on hand.)