cool, spread Orange Filling on one layer; top with remaining layer. Frost with Orange Buttercream Frosting. ORANGE FILLING: In saucepan combine 1/2 cup sugar, 2 tablespoons cornstarch, 1 1/2 teaspoon grated orange peel, and 1/4 teaspoon salt. Gradually blend in 3/4 cup orange juice, 1/4 cup water, and 2 slightly beaten egg yolks. Cook and stir over medium heat till thickened and bubbly. Remove from heat; stir in 2 tablespoons butter till melted. Cool. ----