Heat the remaining 1 tablespoon of neutral oil in the same pan over medium heat. When it begins to smoke, add the onion, garlic, and bay leaves. Cook, stirring often, until the onions begin to caramelize, 8 to 9 minutes. Add the thyme bundle and tomato paste and cook, stirring, until the onions are evenly coated and the tomato paste darkens, 1 minute. Add the wine and cook until reduced by one-third, about 5 minutes. Add the stock, increase the heat to high, bring to a boil, and nestle the brisket back into the braising liquid. Cover and transfer to the oven.