Combine the red wine, red-wine vinegar, water or unsalted beef stock, onion, carrot, leek or celery, garlic, bay leaves, cloves, juniper berries, peppercorns, kosher salt, and granulated sugar in a saucepan. Bring the mixture just to a simmer, then cool it completely.

Place the beef in a nonreactive glass or stainless-steel container and pour the cooled marinade over it. Cover and refrigerate for 2-4 days, turning the roast once daily so it remains fully coated.

Remove the beef from the marinade and pat it very dry. Strain the marinade, reserving the liquid and vegetables separately.

Heat the oil, lard, or clarified butter in a heavy Dutch oven. Brown the roast thoroughly on every side, working in batches if needed to avoid crowding.

Add the reserved vegetables to the pot and cook briefly. Pour in the strained marinade and enough beef stock to bring the liquid about one-third to halfway up the roast.

Bring the liquid to a gentle simmer, cover the Dutch oven, and braise over low stovetop heat or in a 160°C (325°F) oven for 2 1/2-3 1/2 hours. Turn the roast occasionally, cooking until fork-tender.

Transfer the beef to a platter and keep it covered. Strain the braising liquid, pressing the vegetables to extract their flavor, then return the liquid to the pot.

Stir in the crushed ginger snaps or Lebkuchen gradually and simmer until the gravy thickens. Add brown sugar if the vinegar tastes too sharp, and season with salt and pepper.

Rest the roast for 15-20 minutes, then slice it across the grain. Spoon the hot gravy over the slices and serve immediately with your chosen German accompaniments.