3 1/2 c. sifted all purpose flour
2 1/4 c. sugar
5 tsp. baking powder
1 tsp. salt
3/4 c. vegetable shortening
1 1/2 c. milk
4 eggs
2 tsp. vanilla
2 tsp. each: lemon, orange and lime rind
Yellow, red and green food coloring

Grease and flour 3 (9 inch) cake pans. Sift flour, sugar, baking powder and salt. Add shortening, milk, eggs and vanilla. Beat at low speed 1 minute. Beat 3 minutes more on high speed (scrape side of bowl several times). Divide batter into 3 bowls; add lemon rind and yellow food color to 1 bowl; add orange rind and yellow and red food color to 1 bowl; and add lime rind and green food color to the last bowl. Stir each just to blend. Bake at 350 degrees for 30 minutes. Put layers together with lemon filling; frost top and sides with orange cream frosting.

LEMON FILLING:

Combine 1/2 cup sugar, 1/4 cup cornstarch, and 1/4 teaspoon salt in large saucepan. Beat 2 egg yolks and 3/4 cup water with a wire whip until smooth. Cook, stirring constantly with a wooden spoon. Cook until mix thickens and bubbles 1 minute. Remove from heat, stir in 1/3 cup lemon juice and 2 tablespoons butter. Pour into glass bowl; cover with plastic wrap; cool completely. Spread between layers.

ORANGE CREAM FROSTING:

Beat 1/2 cup butter until soft. Beat in 1 package 10x sugar (sifted) and a dash of salt until all sugar is added. Beat in 2 tablespoon orange juice, 2 tablespoon corn syrup and 2 tablespoon vanilla until spreadable. Tint orange with red and yellow food color. Frost top and sides of cake.