To make this Chocolate Snowball Cookies Recipe gluten free, replace the all-purpose flour with a certified gluten-free 1:1 baking flour blend. Verify that the cocoa powder, chocolate chips, powdered sugar, vanilla extract, walnuts, and all packaged ingredients are labeled gluten free or free from gluten-containing additives. Use clean mixing bowls, utensils, measuring cups, and baking sheets to prevent cross-contact with gluten-containing ingredients.