To make this Butter Waffle Cookies Recipe gluten free, substitute the all-purpose flour with a gluten-free 1:1 baking flour blend that is designed to replace regular flour in baked goods. For the best texture, use a blend that already contains xanthan gum or add it according to the package directions if needed. Also check that the baking soda, vanilla extract, almond extract, cinnamon, and brown sugar are certified gluten free if you are baking for someone with celiac disease or a strong gluten intolerance. Since waffle irons can sometimes hold traces of previous batters, be sure the waffle iron is thoroughly cleaned before use to avoid cross-contact.