Pollo Asado Con Llajua (Bolivian Chicken With Spicy Salsa)

"Adapted from Planet Barbecue. Llajua is an extremely hot Bolivian salsa. It is normally made with locoto (rocoto) peppers, but if you can't find them, feel free to use Scotch bonnets or jalapenos, depending on your heat tolerance. Bolivians claim that the peppers need to be cut exactly as described in the recipe, or the flavor will be different. Leave the seeds in if you want it even hotter. You can also use parsley in the salsa if you don't care for cilantro. Prep time includes marinating time. The salsa may be made up to 2 hours in advance. Note: this recipe is best made with bone-in chicken breasts. If you use boneless, reduce cooking time accordingly."