To make these Spinach Balls gluten free, replace the stuffing mix with a gluten-free stuffing mix or a combination of gluten-free breadcrumbs and additional seasonings. Confirm that the parmesan cheese, garlic powder, Italian seasoning, and any prepared breadcrumb or stuffing product are certified gluten free, since some brands may contain additives or be exposed to cross-contact during processing. If you are preparing this recipe for someone with celiac disease or a strong gluten intolerance, make sure your mixing bowl, baking sheet, utensils, and work surfaces are thoroughly cleaned before use.