Filled Sunshine Cake

Ingredients (21)

• Cake:
• 9 eggs, separated
• 1/4 cup warm water
• 1 cup sugar
• 1 cup triple-sifted cake flour
• 1 tsp cream of tartar
• 1/4 tsp salt
• 1 tsp vanilla extract
• French Custard Filling:
• 4 egg yolks, beaten
• 3/4 cup sifted confectioners sugar
• 3/4 cup milk
• 1 cup butter, softened
• 1 tsp vanilla extract
• Boiled Frosting:
• 1 1/3 sugar
• 1/2 cup water
• 3 egg whites
• Pinch of salt
• 1 tsp vanilla extract
• Grated rind of 1 orange