To ensure this Indian Butter Chicken Recipe is fully gluten-free, verify that the tandoori masala and garam masala used are certified gluten-free, as certain spice blends may contain additives or traces of wheat. All other ingredients in this recipe—chicken, butter, cream, tomato sauce, garlic, and onions—are naturally gluten-free. For complete assurance, consider using individual gluten-free spices to create your own masala blends.