The prep time is 15 minutes, cooking time about 3 hours, and cooling down the meat in the refrigerator over night. In other words: Prepare the dish a day before you serve it. It's well worth it.
Brown the meat in a large skillet over medium-high heat from all sides. Add water, ketchup , vinegar , onions , garlic, brown sugar and salt and bring to a boil. Then cover the pan and reduce the heat to medium to low heat. Simmer for about 2-1/2 to 3-1/2 hours, turning the meat from time to time.
Take the brisket from the pan and let it rest for a few minutes . Cut it now against the fibers into slices, stack layers of the slices in a large roasting pan and pour the sauce over all slices. Cover pan and cool overnight in the refrigerator. An hour before serving, scoop fat from the meat, heat, and serve!