Cream butter and 1/2 cup sugar until light and fluffy. Add one egg plus one egg yolk and cake flour. Beat until well blended. Spread in a 13" x 9" x 2" pan. Bake at 400 degrees for 10 minutes. Mix sugar, almond paste or filling, 2 egg yolks and lemon juice in electric mixer until blended. Fold in egg whites and vanilla. Spread over baked crust and sprinkle flaked coconut over top. Bake at 325 degrees for 30 minutes. Cool and cut into bars.