Put the Cheerios™, quinoa flour, baking powder, salt, sugar, cocoa powder and coconut oil in a food processor. Process to mix. Add the egg and vanilla, and continue processing for a few seconds until a very soft dough has formed. Transfer to a plastic bag and freeze for at least 1 hour. You can also freeze overnight. Preheat the oven to 375 °F. Remove the dough from the freezer. Form balls by the rounded teaspoon and roll in powdered sugar. Arrange the cookies, with plenty of space between each dough ball, on a baking sheet lined with a silicone baking mat or greased parchment paper. Bake for 8 minutes. Remove from the oven and let the cookies cool on the baking sheet before transferring to cooling rack to cool completely. Serve and enjoy!