Roasting the garlic mellows its bite and gives the stuffing a subtle hint of flavor. Stuff the chicken breasts up to a day ahead, refrigerate, and cook them just before guests arrive. Garnish each plate with a rosemary sprig.
Using the cilantro stems for the base of the sauce (instead of throwing them in the trash) is a flavorful way to stretch a buck or two. If you can't find skin-on boneless chicken thighs, purchase bone-in and bone them yourself or have the butcher do so.
