Pat your brisket dry and sprinkle it with paprika, thyme, and plenty of salt and pepper; rub it all over the surface on both sides.
Set an ovenproof pot (one in which the brisket will fit fairly snugly is ideal) over medium-high heat and add a generous drizzle of oil. Brown the brisket on both sides, then transfer to a plate and add the onions to the pan. Cook for a few minutes, until starting to soften and turn golden. Add the garlic and cook for another minute.
Return the brisket to the pan and add the tomatoes, stock and bay leaves. Cover and braise at 325F for 3-4 hours, lifting the lid to flip the meat once or twice – and leave the lid off for a bit if you want to reduce the liquid. If it’s cooking off too quickly and looking dry, add a splash more stock, or even some water.
To serve, slice against the grain and spread out on a platter, topped with sauce. If you like, prepare the brisket a day ahead to allow the flavours to develop – cool then refrigerate in the pot overnight, then reheat in the oven when you’re ready for it. Serve leftovers in soft buns, or make tacos or fajitas.