Cake Batter:
Butter, for greasing the pans
1 3/4 cups all-purpose flour, plus more for pans
2 cups sugar
3/4 cups good cocoa powder
2 teaspoons baking soda
1 teaspoon baking powder
1 teaspoon salt
1 cup buttermilk, shaken
1/2 cup vegetable oil
2 extra-large eggs, at room temperature
1 teaspoon pure vanilla extract
1 cup freshly brewed hot coffee


Chocolate Buttercream Frosting:
6 ounces good semisweet chocolate, chopped (i used chips - no hassle of chopping!))
1/2 pound (2 sticks) unsalted butter, at room temperature
1 extra-large egg yolk, at room temperature (i used 2 large egg yolks instead)
1 teaspoon pure vanilla extract
1 1/4 cups sifted confectioners' sugar
1 tablespoon instant coffee powder