In a medium pot, combine equal parts vinegar and water, along with your choice of spices. Stir in brown sugar and bring to a boil. Let it cool completely.

Place your beef roast in a bowl or plastic bag, pour the marinade over it, and refrigerate for 3-4 days, turning occasionally.

Preheat oven to 325°F (163°C). Sear the marinated beef in a Dutch oven until browned on all sides.

Add reserved marinade back to the pot along with chopped onions, carrots, and celery. Pour in beef broth and braise in the oven for 2.5 to 3 hours.

Remove the beef and strain the braising liquid. Reduce the liquid on heat to concentrate flavors, adding cornstarch for thickness if desired.

Let the beef rest for 10-15 minutes before slicing and serve with the thickened sauce.