Preheat oven to 300°F/150°C.

Season both sides of the brisket liberally with black pepper and lightly with salt.

Heat 1 tablespoon of the oil in a 5 quart (4.7 L) Dutch oven over medium-high heat. Sear both sides of the brisket, until browned, about 5 minutes each side. Remove and set aside.

Add remaining 1 tablespoon garlic-infused oil to pot, turn heat down to low-medium, add leek and scallion greens and sauté, stirring frequently, until softened but not browned, about 2 minutes. Whisk in BBQ sauce, water, cider vinegar, brown sugar, cumin, mustard, paprika, thyme and Worcestershire sauce, turn heat up and bring to a boil, scraping up any browned bits from the bottom of the pan and combining everything well. Add meat back to pan; liquid should come almost to the top of the brisket. Spoon some of the sauce on top of the brisket. Seal top of pot with aluminum foil, place lid on top of foil and place in oven.

Braise in the oven for 3 hours. Brisket should be fork tender. Remove brisket to a carving platter and cover with aluminum foil to keep warm while it rests for 10 minutes. Meanwhile, taste the sauce, adjust seasoning as desired. Slice the meat against the grain, or shred with two forks, and serve with sauce. (Reheat in sauce, if necessary). Serve with potatoes, grits, or pile up on a roll with slaw as seen in image. Brisket may be made up to 3 days ahead. Simply store in the sauce and reheat on top of stove.