combine chicken , garlic, oregano, pepper and coarse salt to taste, vinegar, olive oil, olives, capers and juice, and bay leaves. Cover and let marinate, refrigerated, overnight.
Preheat oven to 180ºc.
Arrange chicken in a single layer in large, shallow baking pans and spoon marinade over it evenly. Distribute prunes around the dish pressing into spaces. Pour white wine around them and sprinkle chicken pieces with brown sugar.
Bake for 50 minutes to 1 hour, basting frequently with pan juices. Chicken is done when thigh pieces, pricked with a fork at their thickest, yield clear yellow (rather than pink) juice.
With a slotted spoon transfer chicken, prunes, olives and capers to a serving platter. Moisten with a few spoonfuls of pan juices and sprinkle generously with parsley or cilantro. Pass remaining pan juices in a sauceboat.
To serve Chicken Marbella cold, cool to room temperature in cooking juices before transferring to a serving platter. If chicken has been covered and refrigerated, allow it to return to room temperature before serving. Spoon some of the reserved juices over chicken.