Instructions

1 Grease and flour four 9 inch cake pans. Preheat oven to 325 degrees F (165 degrees C). Sift together flour, cream of tartar, and baking powder four times. Set aside.

2 Beat 8 egg yolks with a rotary or electric beater until very thick, light, and creamy. Add the 2 cups sugar, a few tablespoons at a time, and continue beating until mixture is smooth and pale yellow. Stir in 1 grated lemon rind and juice of 1 lemon. Quickly fold in the flour mixture until well incorporated.

3 In a large glass or metal mixing bowl, whip the 8 egg whites until peaks form. Fold 1/3 of the whites into the batter, then quickly fold in remaining whites until no streaks remain.

4 Spoon into cake pans and bake for 20 to 25 minutes or until cake begins to pull away from sides of pans. Loosen edges with a knife and turn out on cake racks to cool while you prepare the filling and frosting.

5 To Make Lemon Jelly Filling: Mix 6 egg yolks with 2 cups sugar, grated rind of 2 lemons, and juice of 4 lemons. Cook over boiling water, stirring constantly, until sugar dissolves. Add 1/2 cup butter and continue cooking, stirring constantly, for 20 minutes or until filling is smooth and very thick. Cool, then spread between layers of cooled cake.

6 To Make Lemon-Orange Frosting: Beat the 1/4 cup butter until it has the appearance of thick cream, stir in 6 cups confectioners sugar, a little at a time, and continue working until mixture is very smooth. Beat in 1 egg yolk and 2 tablespoons lemon juice. Stir in enough orange juice to make a spreadable frosting, then add grated rind of 1 lemon and 2 grated orange rinds. Spread on sides and top of cake.