- 9 tablespoons unsalted butter, softened
- 2 1/2 cups sifted all-purpose flour*
- 3 squares (3 oz.) unsweetened chocolate
- 1 cup boiling water
- 1 teaspoon vanilla extract
- 2 cups Imperial Sugar Extra Fine Granulated Sugar
- 2 large eggs, separated
- 1 teaspoon baking soda
- 1/2 cup sour cream
- Imperial Sugar Confectioners Powdered Sugar
*Spoon & Sweep method: Use a spoon to fill measuring cup with flour until required amount is obtained. Scooping measuring cup directly into flour bag will firmly pack flour resulting in too much flour required for recipe.
- Preheat oven to 350°F.
- Use 1 tablespoon of butter to grease a 10-inch tube pan. Use 2 tablespoons of flour to flour pan. There should be about 1 7/8 cups of flour left.
- Break up or chop chocolate into small pieces. Place them in a good size mixing bowl with remaining 8 tablespoons of butter.
- Pour in boiling water and let stand until melted. Mix in vanilla and sugar. Whisk in egg yolks, one at a time, beating well after each addition.
- Meanwhile, in a small bowl or measuring cup, mix together baking soda and sour cream. Add them to batter, and whisk in. Sift the flour into batter. Mix well.
- Beat egg whites until stiff (but not dry), preferably in a copper bowl with a wire whisk. Fold them gently but thoroughly into batter. Then, pour batter into prepared tube pan, smoothing top with a rubber spatula.
- Bake for 45 minutes or until cake tester comes out clean. Cool pan on wire rack for 10 minutes.
- Invert onto serving plate, unmold, and cool completely before frosting with frosting of your choice. Sift confectioners powdered sugar on top before serving.