For the Cupcakes

1 3/4 cups all-purpose flour
2 cups sugar
3/4 cups cocoa powder
2 teaspoons baking soda
1 teaspoon baking powder
1 teaspoon kosher salt
1 cup buttermilk, shaken
1/2 cup vegetable oil
2 eggs, at room temperature
1 teaspoon pure vanilla extract
1 cup freshly brewed hot coffee
1 ½ teaspoons instant espresso granules

For the frosting

3 sticks unsalted butter, softened
pinch of fine grain sea salt
2 teaspoons pure vanilla extract
2 pounds confectioners’ sugar, sifted
2 tablespoons unsweetened cocoa powder, sifted
1 tablespoon instant espresso granules dissolved in 1 tablespoon warm water
3-6 tablespoons heavy cream or milk