Traditionally, tabbouleh is made with bulgur wheat, but there are a few acceptable substitutions. The most common substitution in the United States is couscous, which is made from a different variety of wheat.  If you are looking for a gluten-free substitute, you’re in luck! You can make mouthwatering tabbouleh by replacing the bulgur wheat with quinoa or with riced cauliflower, like in this cauliflower tabbouleh recipe.