Add butter, vanilla, peppermint extract, and milk. Blend until the mixture is smooth.
Slowly add in 1 cup of powdered sugar at a time. Mixing directly after each addition. (Until the total of 4 cups of powdered sugar has been added.
Add additional milk or powdered sugar as needed to get a spreadable consistency. (If the icing runs off the cookies, add more powdered sugar.)
With the off set spatula frost each cookie. Immediately after frosting each cookie sprinkle each cookie with finely crushed peppermint.
Return to the wire rack for the icing to set.
ENJOY!
