1/2 cup butter (or margarine)
1 1/2 cups granulated sugar
1 tablespoon orange peel (grated)
2 1/4 cups flour (sifted)
2 teaspoons baking powder
1/4 teaspoon baking soda
1/2 teaspoon salt
3/4 cup water
1/4 cup fresh orange juice
4 egg whites (beat stiff)

Beat butter (or margarine) with sugar until fluffy. Add orange peel. Sift flour, baking powder, soda, and salt and add to butter mixture.

Combine water and orange juice and add alternatively with dry ingredients, beating well. Fold in egg whites. Pour into two 8-inch round greased and floured cake pans. Bake in 375 degree F oven about 30 minutes (or until cake tests done). Cool five minutes and remove from pans. When cool, spread Orange Filling between layers and frost top and sides with Orange Buttercream Frosting.

Orange Filling
1/2 cup granulated sugar
2 tablespoons cornstarch
1 1/2 teaspoons orange peel (grated)
1/4 teaspoon salt
3/4 cup orange juice
1/4 cup water
2 egg yolks
2 tablespoons butter

Combine sugar, cornstarch, orange rind and salt in heavy saucepan. Gradually blend in orange juice, water and beaten egg yolks. Cook over medium heat, stirring constantly until mixture thickens. Cook three minutes. Remove from heat and stir in butter. Cool before spreading between layers.

Orange Buttercream Frosting
6 tablespoons butter
4 1/2 cups confectioners' sugar (sifted)
1 tablespoon orange peel (grated)
Dash salt
4 to 6 tablespoons orange juice

In small deep bowl, cream butter, confectioners sugar, orange rind, salt and orange juice to spreading consistency. Beat until smooth and creamy.