Preheat your oven to 350 degrees F. In a large dutch oven heat the oil over high heat. Salt and pepper the brisket on both sides and then sear the meat in the dutch oven for about 4 minutes on each side. Remove and set onto a plate. Add the onions, celery and carrot to the dutch oven and saute for 8 minutes, add more oil if needed. Add the garlic and saute for 2 minutes more. Add the tomato paste, stewed tomatoes and beef stock and bring to a simmer. Add the brisket back to the dutch oven and nestle it into all the vegetables. Place into heated oven and let it do its thing for 3 hours. Once done, remove from oven and keep over low heat on stove-top. Using 2 forks, shred the brisket and then let sit over low heat for 20 minutes more. Adjust seasoning as needed. You can either use the brisket right away, or transfer to a container and use the following day.
