Combine all dry rub ingredients together and rub meat the night before braising. Refrigerate, covered in plastic wrap, until the next day.
Preheat the oven to 325°F Heat the oil over high heat in a heavy casserole or Dutch oven just large enough to hold the pork. Brown the pork on all sides, 7 to 8 minutes. Remove and set aside. Pour off all but about 1 tablespoon of the fat from the pot and add the pearl onions, leeks, and carrots. Lower the heat to medium, cover the pot, and cook until the vegetables have softened, about 5 minutes.
Pour in the port, stock and honey and scrape up any browned bits from the bottom of the pot. Add the prunes, the optional brandy, and the bay leaves and bring to a boil. Put the pork back in and spoon some of the prunes and vegetables over the top. Cover the pot with foil and fit the lid on tightly.
Place the pot in the middle of the oven and cook for about 1-1/2 hours, or until the pork is quite tender and registers 160° to 165°F on an instant-read meat thermometer. Remove the pork from the pot and cover loosely to keep warm. The final temperature of the meat after resting for 10 minutes or so may read 170° to 175°F.
Skim off any fat from the cooking juices. Remove 6 of the prunes and puree them in a food processor or blender. Stir the puree back into the sauce to thicken it. Remove the bay leaves and taste the sauce for salt and pepper. Remove the strings from the pork if necessary, and carve into 1/2-inch slices. Serve with the sauce and prunes and vegetables.