Preheat oven to 350 degrees. Grease and flour two 9x1 1/2 inch round cake pans; set aside.
Finely grate 3 tablespoons of peel from 3 oranges. Squeeze juice from 2 oranges to measure 1/2 cup juice. Section remaining orange. Set aside.
In a large mixing bowl, beat egg whites to soft peaks. Gradually add 1/2 cup sugar, beating to stiff peaks. In another large mixing bowl combine flour, baking powder, salt and remaining 1 cup sugar.
In a separate bowl, combine milk and oil. Add orange juice and egg yolks, beat 1 minute. Gently fold in egg white mixture until combined. Fold in 1 Tbs of orange peel, saving the rest for the frosting. Divide batter evenly between pans.
Bake in preheated oven for 30 to 35 minutes or until a wooden toothpick inserted near center comes out clean. Cool completely on wire racks. remove from pans. Frost with Orange Fluff Frosting. Top with reserved orange sections. Makes 12 servings. Enjoy!