Makes 4 1/2 cups
(4 sticks) unsalted butter, at room temperature
finely grated lemon zest
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.