- 1 tablespoon instant espresso powder
- 2 cups (4 sticks) unsalted butter, at room temperature
- 1 pound confectioners’ sugar (about 3 3/4 cups), sifted
- 1 teaspoon pure vanilla extract
- pinch kosher salt
- In a small bowl, stir together the espresso powder with 1 tablespoon hot water until the powder is dissolved. Using an electric mixer, beat the butter on high until light and fluffy, 3 to 5 minutes. Reduce mixer speed to low. Gradually add the sugar, then the espresso mixture, vanilla, and salt, and beat until smooth, scraping down the sides of the bowl as necessary.