Separate 5 eggs. Let stand at room temperature 1 hour. Assemble all ingredients and utensils needed. Use 10 inch tube pan 4 inches deep or 13 x 9 oblong pan. Preheat oven. Grate orange rind. Sift flour once, before measuring. Sift together into medium bowl:

2 1/2 c. sifted cake flour
3 tsp. baking powder
1 1/2 c. granulated sugar
1 tsp. salt

Make hollow in flour mixture, add:

1/2 c. salad oil
5 egg yolks (3/8th c.)
3/4 c. cold water or strained orange juice
3 tbsp. grated orange rind

Beat or stir medium speed until smooth about 1 minutes. Scrape bowl. Wash and dry beaters thoroughly. Place in large bowl:

1 c. egg whites (7 to 8)
1/2 tsp. cream of tartar

Beat at high - whip speed until whites form very stiff peaks (about 2 minutes). DO NOT OVER BEAT. Pour yolk mixture over whites, gently cutting and folding in with rubber spatula and up the side and over. Turn bowl until blended. DO NOT STIR. Pour into pan.

Bake tube pan at 325 degrees for 55 minutes, then at 350 degrees for 10 to 15 minutes. Bake 13 x 9 pan at 350 degrees for 45 to 50 minutes. Bake until surface springs back when lightly touched. Invert pan at once. Leave until cold. Loosen with spatula and remove.