Mile-High Chocolate Cake: 2000s Recipes + Menus : gourmet.com

Ingredients

• 5 oz fine-quality unsweetened chocolate, chopped
• 2 1/4 sticks unsalted butter, softened
• 2 3/4 cups sifted cake flour (not self-rising; sift before measuring)
• 1/4 cup unsweetened cocoa powder (not Dutch-process)
• 2 teaspoons baking soda
• 1 teaspoon baking powder
• 1/2 teaspoon salt
• 4 large eggs, at room temperature 30 minutes
• 1 cup granulated sugar
• 1 cup packed light brown sugar
• 1 1/2 teaspoon pure vanilla extract
• 2 cups sour cream
• 1 cup sugar
• 6 tablespoons all-purpose flour
• 6 tablespoons unsweetened cocoa powder (not Dutch-process)
• 1 1/2 cups whole milk
• 4 oz fine-quality unsweetened chocolate, finely chopped
• 1 tablespoon pure vanilla extract
• 6 sticks (1 1/2 pound) unsalted butter, at room temperature