When ready to bake, preheat oven to 350°Prepare cookie sheets with silicone mat or parchment paper.
Using a cookie scoop remove dough and drop them on prepared cookie sheet. If you don't have a cookie scoop take 1 spoonful maybe a tablespoon of dough roll into a ball with your hands instead.
Bake for about 8-10 minutes in the preheated oven, or until edges are JUST barely browning. These cookies are best when slightly under done. Super soft and chewy!
With a handheld or stand mixer fitted with a paddle or whisk attachment, beat the butter on medium speed until creamy – about 2 minutes.
Add confectioners’ sugar, cocoa powder,3 tablespoons heavy cream or milk, salt, and vanilla extract. Beat on low speed for 30 seconds, then increase to high speed and beat for 1 full minute. Add 1/4 cup more confectioners’ sugar or cocoa powder if frosting is too thin or another tablespoon of heavy cream or milk if frosting is too thick.
Spread the frosting onto the flat side of one cookie and sandwich with the other. You can pipe the frosting or just add as much frosting as you like with a spoon. Repeat with remaining.