Sprinkles Vanilla Frosting

2 sticks unsalted butter, firm but not cold

3 1/2 cups powdered sugar

1/2 tsp milk

1/2 tsp vanilla

1/8 tsp salt

Beat butter and salt on medium speed until light and fluffy, about 2 minutes.  Reduce the speed to low, gradually add the confectioner's sugar and beat until incorporated.  Add the vanilla and milk and beat until smooth and creamy.  Do not over mix.  Add additional milk, 1 tsp at a time, if frosting is not spreadable.