In a small mixer bowl sift together cake flour, sugar, baking powder, and salt; make a well in the center.
Add cooking oil, egg yolks, water, lemon peel, and vanilla.
Beat mixture at high speed of electric mixer till satin smooth, about 5 minutes.
Wash beaters thoroughly.
In large mixer bowl combine egg whites and cream of tartar; beat at medium speed till very stiff peaks form.
Pour batter in a thin stream over entire surface of egg whites; fold in gently.
Pour into ungreased 10-inch tube pan.
Bake at 325° till cake springs back and leaves no imprint when lightly touched, about 70 minutes.
Invert cake in pan; cool.
Using a spatula, loosen cake from pan; remove.