20 Tablespoons (2 and 1/2 sticks) unsalted butter, softened.
2-1/2 cups confectioners’ sugar, sifted (for a thicker icing, add more confectioners’ sugar).
1/8 teaspoon salt
1 teaspoons vanilla extract (I also add 1/2 teaspoon almond extract to the icing).
2 Tablespoons heavy cream
In a stand mixer fitted with the wisk attachment, beat butter at medium-high speed until smooth, about 20 seconds.
Add confectioners’ sugar and salt; beat at medium-low speed until most of the sugar is moistened, about 45 seconds.
Scrape down the bowl and beat at medium speed until incorporated, about 10 seconds. Then increase the speed to medium-high and beat until light and fluffy, about 4 minutes, scraping down bowl once or twice.