How to Make It
In a food processor, combine the vinegar, brown sugar, olive oil, olives and the 3 crushed garlic cloves; process to a coarse paste. Season the chicken with salt and pepper. Put the chicken in a bowl and pour the marinade over it. Add the wine and water and turn the chicken to coat. Cover and refrigerate for at least 2 hours or overnight.
Preheat the oven to 400°. Arrange the chicken pieces, skin side up, in a large flameproof roasting pan. Scatter the fennel and unpeeled garlic around the chicken. Cover with foil and bake on the top shelf of the oven for 30 minutes. Turn the fennel and bake for 20 minutes. Uncover the pan, raise the oven temperature to 500° and bake for 20 minutes or until the chicken is lightly browned and cooked through.
Transfer the chicken, fennel and garlic to a large heatproof bowl. Add the currants and soy sauce to the juices in the pan and cook over moderate heat until slightly reduced, about 5 minutes. Cover a platter with the pitas, top with the chicken, fennel and garlic and pour the currant sauce over all. Garnish with the oregano sprigs and serve.