Into a bowl, sift the flour, cocoa powder, salt, and baking powder. Set aside.
In another bowl, add sugar, butter and vanilla. Beat with a hand mixer for 1-2 minutes or until fluffy. Then, add the egg and food coloring and beat until well incorporated.
Add the milk and beat to incorporate.
Add the dry mixture and mix on low just until no dry ingredients are left.
Wrap the dough in plastic wrap and freeze for 20-30 minutes or until solid enough to form dough balls. You can also refrigerate the dough overnight.
Preheat the oven to 180C (355F) and line a baking sheet with parchment paper.
Form 13 cookie dough balls and roll them in a thick layer of powdered sugar.
Place the cookie balls on the baking sheet so they have at least 2” (4cm) space in between. Bake for 13- 15 minutes or until they have spread and are crinkly.
Remove from the oven and let cool for 2 minutes on the baking sheet before transferring to a cooling rack to cool completely.