Preparation / Directions:
1. Mix together flour, sugar, baking powder and salt in mixing bowl.
2. Make a well and add in order: oil, egg yolks, water, lemon peel and vanilla; beat until smooth.
3. Beat egg whites and cream of tartar in large mixing bowl on high speed until stiff peaks form.
4. Pour egg yolk mixture gradually over beaten whites, gently folding with rubber spatula just until blended.
5. Pour into ungreased 10-inch tube pan; bake in preheated 325 F. oven until top springs back when touched lightly, about 1 1/4 hours.
6. Invert pan on funnel; let stand until cake is cold.
7. Remove from pan; frost with Lemon Butter Frosting.
Lemon Butter Frosting
1. Combine butter and confectioners' sugar.
2. Beat in lemon peel and juice until frosting is of spreading consistenc