INGREDIENTS
1
Egg yolk, large
2
Eggs, large
1 3/4 cups
All-purpose flour
1 tsp
Baking powder
2 tsp
Baking soda
6 oz
Chocolate, good semisweet
1
Chocolate buttercream
3/4 cup
Cocoa powder, good
1 1/4 cups
Confectioners' sugar
1 tsp
Kosher salt
2 cups
Sugar
2 tsp
Vanilla, pure
1/2 cup
Vegetable oil
1 cup
Coffee, hot
1 tbsp
Instant coffee, powder
1/2 lb
unsalted butter, unsalted
1
Butter
1 cup
Buttermilk