In a saucepan, combine equal parts vinegar and water, bringing them to a gentle boil. Stir in your spices and brown sugar, allowing it to simmer for about 5 minutes. Remove from heat and let cool.

Place the beef roast in a large bowl or resealable bag, pouring the cooled marinade over it. Ensure the meat is completely submerged. Seal and refrigerate for 3-4 days, turning daily.

Preheat your oven to 325°F (163°C). In a Dutch oven, heat oil over medium-high heat. Remove beef from marinade, pat dry, and brown on all sides for about 5 minutes.

Add the reserved marinade along with chopped onions, carrots, and celery into the Dutch oven. Pour in enough beef broth to reach halfway up the meat. Cover and bake for 2.5 to 3 hours until fork-tender.

Remove the beef from the Dutch oven and strain the cooking liquid into a saucepan. Bring to a simmer and reduce until thickened, about 10-15 minutes. If desired, mix cornstarch with water and stir in to thicken.

Allow the beef to rest for 10-15 minutes before slicing. Serve with creamy mashed potatoes, red cabbage, or spaetzle.