- 2 cups (4 sticks) unsalted butter, at room temperature
- 2 tablespoons finely grated lemon zest
- 1 pound confectioners’ sugar (about 3 3/4 cups), sifted
- pinch kosher salt
- Using an electric mixer, beat the butter and lemon zest on high until light and fluffy, 3 to 5 minutes. Reduce mixer speed to low. Gradually add the sugar, then the salt, and beat until smooth, scraping down the sides of the bowl as necessary.