1. Bring the wine, vinegar, 2/3 cup water, onions, sugar, nutmeg, allspice, peppercorns, bay leaves, and salt to a boil in a saucepan. Let cool completely.
2. Place the beef in a bowl and pour in the cooled marinade. Cover with plastic wrap and refrigerate, turning the meat over every 8 hours or so, for 2–3 days.
3. Preheat the oven to 350°F (180°C). Lift the beef from the marinade, drain well, then pat dry with paper towels. Strain the marinade into a bowl, discarding the spices.
4. Heat the oil in a large flameproof casserole over medium-high heat. Add the beef and cook about 10 minutes, until browned on all sides. Transfer to a plate. Add the onion and celery to the casserole and cook, stirring constantly, for about 5 minutes, until beginning to brown. Sprinkle in the flour and stir for 1 minute. Stir in 2 cups of the reserved marinade and bring to a boil, stirring often.
5. Return the beef to the casserole and baste with the liquid. Cover tightly. Bake for about 2¼ hours, or until very tender.
6. Transfer the beef to a serving platter and tent with aluminum foil. Strain the cooking liquid into another saucepan, bring to a boil, and cook until reduced to about 1¼ cups. Whisk in the gingersnaps and cook, whisking often, until the sauce is smooth and lightly thickened. Season with salt and pepper. Slice the beef crosswise, spread the slices on the platter, and spoon some of the sauce over. Serve hot, with the rest of the sauce passed on the side.