This dish is similar to a Moroccan tagine but comes with something extra: A pearl couscous side dish cooks along with the vegetables and chicken in one pot. Ras el hanout, a Middle Eastern spice blend gives the chicken a flavor that will fill your mouth from around the world. Ras el hanout spice blend is available at specialty shops, or you can make your own; see NOTE below.
MAKE AHEAD: The casserole can be assembled 1 day in advance and refrigerated.
