Preheat oven to 350ºF.
Generously butter two round 8 inch cake pans.
You will need three bowls (two large, one small).
Beat egg whites until soft peaks form. Gradually add 1/2 cup
sugar while continuing to beat until very stiff in large bowl
of mixer.
Mix egg yolks, oil, water, and vanilla together in a small
bowl.
Sift together the dry ingredients into the other large bowl -
1 cup sugar, flour, baking powder, and salt.
Add the yolk mixture to the dry ingredients. Mix well.
Fold in stiffly beaten egg whites and gently incorporate.
Pour into prepared pans.
Bake at 350ºF for about 25 minutes, until sides shrink and top
springs back in the center.
Turn onto a rack immediately and let cool.