5-7 lb. brisket, first or second cut (grass fed not recommended)
1/4 cup extra virgin olive oil, divided
2 large brown onions, peeled and sliced
1 lb. carrots, peeled and sliced
1 lb. celery, peeled and sliced
1 large can (1 lb. 12 oz.) tomatoes - whole, diced, or crushed
10 peeled whole garlic cloves
1/2 cup brown sugar
1/4 cup vinegar (I like apple cider vinegar, but white vinegar works too)
2 cups beef or chicken broth, divided
Salt and pepper
Large roasting pan, blender or food processor, large skillet, spatula, aluminum foil, large glass or ceramic baking dish (if making ahead), plastic wrap (if making ahead), sharp carving knife