In a large bowl, combine the red wine vinegar, beef broth, onion, carrots, celery, garlic, bay leaves, peppercorns, brown sugar, ginger, mustard, salt, and pepper. Mix well to create the marinade.

Place the beef roast in a large resealable plastic bag or a glass dish, and pour the marinade over the meat. Make sure the meat is completely covered with the marinade. Seal the bag or cover the dish and refrigerate for at least 24 hours, turning the meat occasionally.

After marinating, remove the meat from the marinade and pat it dry with paper towels. Reserve the marinade.

In a large Dutch oven or heavy-bottomed pot, heat the vegetable oil over medium-high heat. Brown the beef roast on all sides, then remove the meat from the pot and set it aside.

Add the flour to the pot and whisk it into the remaining oil to create a roux. Cook for a few minutes until the roux is lightly browned.

Slowly pour in the reserved marinade, whisking continuously to prevent lumps. Bring the liquid to a simmer.

Return the beef roast to the pot, cover with a lid, and simmer on low heat for about 2-3 hours, or until the meat is tender and can be easily shredded with a fork.

Once the meat is cooked, remove it from the pot and let it rest for a few minutes before slicing.

If desired, you can thicken the gravy by simmering it uncovered for a few more minutes until it reaches your desired consistency.

Serve the Sauerbraten slices with the gravy on top, accompanied by traditional sides like potato dumplings, red cabbage, or mashed potatoes.

Enjoy!