best birthday cake

INGREDIENTS

• [
• Some of you have responded that you find the Chocolate Sour Cream Frosting a bit too sour for your tastes. And it is sour, of course, as sour cream is the base. However, if you're looking for an equally speedy dark chocolate frosting more along the lines
• from the
• a spin. It's wonderful.]
• 4 cups plus 2 tablespoons (480 grams) cake flour (not self-rising)
• 2 teaspoons (10 grams) baking powder
• 1 1/2 teaspoons baking soda
• 1 teaspoon (5 grams) table salt
• 2 sticks (1 cup, 1/2 pound or 225 grams) unsalted butter, softened
• 2 cups (400 grams) sugar
• 2 teaspoons (10 ml) pure vanilla extract
• 4 large eggs, at room temperature
• 2 cups buttermilk (475 ml), well-shaken
• 15 ounces semisweet or bittersweet chocolate, chopped
• 1 1/4 teaspoons instant espresso (optional, but can be used to pick up the flavor of average chocolate)
• 2 1/4 cups sour cream, at room temperature
• 1/4 to 1/2 cup light corn syrup
• 3/4 teaspoon vanilla extract