Beat butter until creamy, then add sugars. Beat in eggs and vanilla. Combine flour, soda, and cocoa, then add to the butter mixture, beating well.
Use a medium cookie scoop to form cookies, then place them on a cookie sheet that’s been lined with parchment paper or foil and sprayed with cooking spray. Bake for 7-8 minutes at 375 degrees. If your oven tends to bake quickly, check them around 6 minutes–don’t over bake!
Remove the cookies from the cookie sheet as soon as possible, and let cool completely on a cooling rack.
Make the frosting by beating the powdered sugar and butter together, adding the milk until you get the desired consistency. Start with less milk, and then add more a little at a time if you need. ( I like using half and half for a richer flavor, but a higher fat milk works well too. ) Add the salt and the peppermint extract and mix well. Drop in the food coloring until you get the desired color–whether you like it lighter or brighter!
When the cookies are cool, frost them with the Peppermint Frosting, and sprinkle the crushed peppermint on top.
P.S. This frosting is fabulous on brownies too…