In a medium bowl, stir together cookie mix, cocoa, baking soda and salt; set aside.
In a large bowl, whisk together egg, coconut oil, food coloring and sour cream.
Stir flour mixture into the wet mixture with a wooden spoon to combine. Cover and refrigerate until firm, 2 hours to overnight.
Preheat the oven to 300 degrees. You will be using two racks, one on the top third shelf and the other on the bottom third shelf of the oven.
Line two baking sheets with parchment paper.
Place confectioners' sugar in a medium bowl.
Roll the dough into tablespoon sized balls and toss in confectioners' sugar to coat. While in the bowl, with a spoon, press ball to slightly flatten. (I prefer to do this in the bowl, to avoid making a huge mess everywhere with the powdered sugar)
Make sure cookie is well coated with sugar.
Place the cookies 2 inches apart on the prepared baking sheets.
Bake. Switch the pans from top to bottom shelf half way through, until the cookies are puffy and firm to the touch, approximately 17 minutes.
Let the cookies cool completely on the sheet before removing.