Black Pepper-Cumin Chicken and Onion Traybake

This baking-sheet dinner was inspired by musakhan, a Palestinian chicken and onion dish seasoned with sumac and warm spices. The broiler makes quick, easy work of cooking while also delivering flavorful browning. The onions, arranged under the chicken thighs, char in spots and release moisture as they cook; their juices, combined with the chicken’s, form a sauce to drizzle on at the end, keeping the dish moist and succulent. Slice the onions about ½ inch thick so they soften but retain some texture. Taboon bread is a traditional component of musakhan, but serve this with any type of soft flatbread.