2 3/4 cups all-purpose flour
3 teaspoons baking powder
1 teaspoon salt
2/3 cup butter
1 1/2 cups white sugar
3/4 cup champagne
6 egg whites

1) Preheat oven to 350 degrees F (175 degrees C). Butter a 10 inch round cake pan.
2) In a large bowl, cream together butter and sugar until very light and fluffy. Sift flour, baking powder, and salt together, and then blend into creamed mixture alternately with champagne.
3) In a large clean bowl, beat egg whites until stiff peaks form. Fold 1/3 of the whites into batter to lighten it, then fold in remaining egg whites. Pour into prepared pan.
4) Bake at 350 degrees F (175 degrees C) for 25 to 30 minutes, or until a toothpick inserted into the cake comes out clean.