Chocolate Layer Cake | America's Test Kitchen

Ingredients

• 1 1/2 cups (7½ ounces/213 grams) all-purpose flour
• 1 teaspoon baking soda
• 1/2 teaspoon baking powder
• 1/4 teaspoon salt
• 1 1/4 cups boiling water
• 4 ounces (113 grams) unsweetened chocolate, chopped
• 1/2 cup (1 1/2 ounces/43 grams) Dutch-processed cocoa powder
• 1 teaspoon instant espresso powder or instant coffee powder
• 10 tablespoons unsalted butter, softened
• 1 1/2 cups packed (10 1/2 ounces/298 grams) light brown sugar
• 3 large eggs, room temperature
• 1/2 cup sour cream, room temperature
• 1 teaspoon vanilla extract