INGREDIENTS
1 cup boiling water
3/4 cup unsweetened natural cocoa powder
1 3/4 cups all-purpose flour
1 1/2 tsp. baking soda
1/4 tsp. fine sea salt
2 cups granulated sugar
10 Tbs. (1 1/4 sticks) unsalted butter, at room temperature
3 eggs
1 tsp. vanilla extract
1 1/4 cups buttermilk
3 3/4 cups confectioners’ sugar
1 cup unsweetened natural cocoa powder
8 Tbs. (1 stick) unsalted butter, at room temperature
1 tsp. vanilla extract
1 cup heavy cream, or as needed