Ingredients

4 sticks (1 pound) unsalted butter, softened 

6 cups sifted confectioners' sugar 

1/2 teaspoon vanilla extract 

1 pinch of salt 

Preparation

Put butter in bowl of an electric mixer. Beat on medium-high speed until pale and creamy, about 2 minutes. Reduce speed to medium; add sugar 1/2 cup at a time, mixing well, about 5 minutes total. Add vanilla and salt. Raise speed to medium-high; beat until smooth, about 1 minute more.