Preheat the oven: Preheat your oven to 325°F (160°C).

Sear the brisket: Season the brisket generously with salt and pepper. Heat olive oil in a large Dutch oven over medium-high heat. Sear the brisket on all sides until browned, about 4-5 minutes per side. Remove the brisket from the pot and set aside.

Sauté the onions and garlic: In the same pot, add the sliced onion and minced garlic. Sauté for about 5 minutes, until softened and fragrant.

Deglaze with low-carb stout: Pour the low-carb stout into the pot, scraping up any browned bits from the bottom. Let the stout simmer for 2-3 minutes to reduce slightly.

Add remaining ingredients: Stir in the beef broth, tomato paste, Worcestershire sauce, bay leaves, and fresh thyme. Return the brisket to the pot, making sure it's partially submerged in the liquid.

Braise the brisket: Cover the Dutch oven with a lid and transfer it to the preheated oven. Braise for 3-4 hours, or until the brisket is tender and easily pulls apart with a fork. Check halfway through and add more broth if necessary.

Rest and slice: Remove the brisket from the oven and let it rest for 10-15 minutes before slicing. Serve with the braising liquid spooned over the top.

Garnish and serve: Garnish with fresh parsley and serve hot.