boneless, skinless chicken breast or thighs (about 500 grams) • Shawarma seasoning mix (such as Maggi or any available brand) • plain yogurt • olive oil • medium onion, sliced into thin strips • tomato, diced into small cubes • For serving: • Pita bread, flatbread, or flour tortillas • Garlic sauce (toum) • Pickles • French fries • Coleslaw