Preheat your oven to 300°F (150°C).
Season the brisket generously with salt and pepper on both sides.
In a large oven-safe pot or Dutch oven, heat the olive oil over medium-high heat. Sear the brisket for about 4-5 minutes on each side until browned. Remove the brisket and set aside.
In the same pot, add the sliced onion and cook for about 5 minutes until softened. Add the minced garlic and cook for an additional minute.
Pour in the beef broth and red wine (if using), scraping the bottom of the pot to release any browned bits.
Stir in the brown sugar, Worcestershire sauce, Dijon mustard, thyme, and smoked paprika.
Return the brisket to the pot, fat side up, so the fat bastes the meat as it cooks. Cover the pot with a lid or aluminum foil.
Place the pot in the preheated oven and braise for 3 to 4 hours, or until the brisket is fork-tender.
Once cooked, remove the brisket from the pot and let it rest for 15 minutes before slicing.
Serve slices of brisket with the pan juices spooned over the top and garnish with fresh parsley.