Preheat the oven to 350 F. Prepare a large baking sheet with parchment paper. I like using parchment paper for baking to prevent sticking and easy removal.
In a large mixing bowl, mix together the flour, coconut sugar, cocoa powder, baking powder, salt and tapioca flour.
In a separate mixing bowl, mix together the egg, melted coconut oil and peppermint extract.
Add the wet ingredients to the dry ingredients until it becomes a brownie-like texture. Fold the chocolate chips into the batter.
Scoop the dough onto the cookie sheet in 12 round balls, flattening them slightly. Use your thumb to press the center of each cookie to make a little dent for the marshmallow after baking.
Bake 9-12 minutes or until the outside edges are firm.
Remove the baking sheet from the oven. Place a marshmallow in the center of each cookie, then remove and cool completely on a wire baking rack. You can optionally sprinkle with crushed candy canes if you like.