You will need:
1/2 c (one stick) butter, softened
2 c powdered sugar
1 tsp vanilla flavoring (I used butter rum flavoring)
2-4 tsp milk
Mix softened butter and 1 cup of powdered sugar until incorporated
Add second cup of powdered sugar and mix.
Add vanilla flavoring and mix.
If the icing is too thick add a teaspoon of milk at a time and stir until its consistency is just where you want it.
It also helps, after making Tasty Frosting, to have a Delicious Chocolate Cake handy.