Preheat oven to 350˚F. Combine salt, pepper, paprika, and oregano in a small bowl, then rub all over brisket.

​Heat oil in an ovenproof enameled cast iron pot or other heavy pot with a tight-fitting lid, just large enough to hold brisket snugly, over medium-high heat. Add brisket to pot and brown on both sides, about 10 minutes per side. Transfer brisket to a platter and pour off fat from pot. Add stock, tomatoes, and bay leaves to pot and scrape any browned bits stuck to bottom of pot with a wooden spoon. Return brisket and any accumulated juices to pot and scatter onions and garlic over meat. Cover pot, transfer to oven, and braise brisket for 1 hour. Uncover pot and continue to braise brisket for another hour.

​Push some of the onions and garlic into braising liquid surrounding brisket. Check meat for tenderness by piercing center with tip of a sharp-pointed knife; it should slide in easily when fully cooked. Cover pot, return to oven, and continue to braise brisket, checking on tenderness of meat occasionally, until very tender when pierced, up to 2 hours more.

Transfer brisket to a cutting board and loosely cover with foil. The onions and garlic in the pot should be very soft, and braising juices should be rich and saucy. If juices are thin, transfer pot to top of stove and simmer over medium heat until juices thicken, about 5 minutes. Slice brisket across the grain and transfer to a warm serving platter. Spoon onions, garlic, tomatoes, and juices on top. Discard bay leaves before serving.

​Note: This is much better the next day; if time permits, cook it a day before serving and reheat gently. We served this buffet-style with French bread for sandwiches; used an immersion blender to puree the tomatoes and onions into a thick sauce.