To make this Peppermint Sugar Cookies Recipe gluten free, replace the all-purpose flour with a certified gluten-free 1:1 baking flour blend. Verify that the baking powder, chocolate chips, peppermint extract, vanilla extract, crushed peppermint candies or candy canes, and all packaged ingredients are labeled gluten free or free from gluten-containing additives. Use clean mixing bowls, utensils, measuring cups, baking sheets, and cooling racks to prevent cross-contact with gluten-containing ingredients.