Grilled chicken shawarma with charred red onion, naan, and tahini, charred red onion

Boneless skinless chicken breasts, naan bread (enriched wheat flour (wheat flour, niacin, reduced iron, ascorbic acid as dough conditioner, thiamine mononitrate, riboflavin, enzyme, folic acid), buttermilk (skim milk, dry buttermilk, bacterial culture), water, soybean and/or canola oil, cultured wheat flour, eggs, sugar, baking powder (sodium acid pyrophosphate, sodium bicarbonate, cornstarch, monocalcium phosphate), sea salt, ghee (clarified butter), wheat gluten, dextrose, dextrin, vegetable fiber, yeast), persian cucumber, red onion, grape tomatoes, lemon, tahini paste (sesame seeds), garlic, kabsa spice blend (spices, ground chiles, turmeric saffron powder), parsley, cayenne pepper (dried chiles).