- 8 (1 ounce) squares white chocolate
- 1/2 cup hot water
- 1 cup butter
- 1 cup white sugar
- 4 egg yolks
- 1 teaspoon vanilla extract
- 2 1/2 cups sifted all-purpose flour
- 1 teaspoon baking soda
- 1 cup buttermilk
- 4 egg whites, beaten
- Preheat oven to 350 degrees F (175 degrees C). Grease and flour a 9x13 inch pan. Sift together the flour and baking soda; set aside.
- Chop the white chocolate and place it in a medium bowl. Pour the hot water over it and stir until chocolate is melted and smooth. Allow to cool to room temperature.
- In a large bowl, cream together the butter and sugar until light and fluffy. Beat in the egg yolks one at a time, then stir in the melted white chocolate and vanilla. Beat in the flour mixture alternately with the buttermilk, mixing just until incorporated.
- In a large glass or metal mixing bowl, beat egg whites until stiff peaks form. Fold 1/3 of the whites into the batter, then quickly fold in remaining whites until no streaks remain.
- Pour batter into prepared pan. Bake in the preheated oven for 30 to 35 minutes, or until a toothpick inserted into the center of the cake comes out clean. Allow to cool.