The sauce contains no fresh tomatoes or herbs at all — its dark color and sweetness come entirely from dried raisins cooked down until they nearly caramelize.
Not to be confused with the herby North African marinade of the same name, Sfax's charmoula is a dark, sweet-savory sauce of pureed dried raisins and slow-cooked onions in olive oil, spiced with cloves, cumin, chili and cinnamon, served over salted, dried fish.