1. Beat egg whites until frothy, adding 1 cup sugar. Set aside.
2. Mix the sugar, baking powder, flour, salt and soda in a separate bowl.
3. Then add the olive oil, mashed bananas and 1/2 of the buttermilk and vanilla. Beat for about 2 minutes. Add the rest of the buttermilk and egg yolks. Beat again for about 2 minutes.
4. Fold in the beaten egg whites. Pour into 2 greased 9 inch cake pans and bake 30 minutes in a 350 degree oven.
5. Frost with your favorite icing.