01 - Preheat the oven to 325°F.
02 - Pat the brisket dry and season all sides evenly with kosher salt and freshly ground black pepper.
03 - Heat olive oil in a large ovenproof Dutch oven over medium-high heat. Sear the brisket for 3 to 4 minutes on each side until a rich brown crust forms. Remove brisket and set aside.
04 - In the same pot, add sliced onions, carrots, and celery. Cook for 5 minutes, stirring occasionally, until softened. Add minced garlic and cook for an additional 1 minute.
05 - Stir in tomato paste, smoked paprika, and dried thyme. Cook for 1 minute to release the aroma.
06 - Add crushed tomatoes, beef stock, Worcestershire sauce, brown sugar, Dijon mustard, and bay leaf. Stir thoroughly to blend all flavors.
07 - Nestle the seared brisket back into the sauce, spooning some of the sauce over the top to coat.
08 - Cover the pot tightly with a lid or aluminum foil. Transfer to the oven and braise for 3 to 3.5 hours, until the meat is fork-tender.
09 - Remove the brisket from the pot and let it rest for 10 minutes before slicing against the grain to ensure tenderness.
10 - Skim excess fat from the sauce if needed. Simmer on the stovetop to reduce and thicken the sauce as desired.
11 - Serve sliced brisket with generous amounts of sauce and vegetables.