2 cups powdered sugar
1/2 cup unsalted butter, softened
2 tablespoons milk or heavy cream
1 teaspoon vanilla extract
Pinch of salt
Beat the butter until smooth
Add the powdered sugar gradually
Mix in the milk and vanilla
Add more milk for a thinner icing
Add more powdered sugar for a thicker icing
Beat until light and fluffy
Spread or pipe onto the cooled cake