Ingredients:
For the Cake:
- 2 cups all-purpose flour
- 2 cups sugar
- 1/2 teaspoon baking soda
- 1/2 teaspoon salt
- 2 large eggs plus 2 yolks
- 2 teaspoons vanilla extract
- 1/4 cup sour cream
- 8 ounces semisweet chocolate, chopped
- 4 tablespoons unsalted butter