Preheat oven to 325°F.
In a small bowl, combine brown sugar, oregano, paprika, minced fresh thyme, and garlic powder. Set bowl aside until ready to use.
Dry the brisket with paper towels, place it on a half-sheet pan, and let it come to room temperature. Sprinkle half of the Kosher salt and freshly ground black pepper on one side. Heat two tablespoons of vegetable oil over medium-high heat in a large Dutch oven.1 Place the brisket, seasoned side down, into the hot pot. Then, season the other side with the remaining salt and pepper and sear for about six minutes. Use a pair of large tongs to flip the brisket over and sear the other side for about six minutes. Then, transfer the brisket to a clean half-sheet pan.
Reduce the heat to medium-low, add chopped onions to the pot, and sauté for about five minutes. Use a wooden spatula to scrape the bottom of the pot as you stir the onions around. Then, add minced garlic, tomato paste, and whole ground mustard. Continue stirring for about a minute, or until the garlic becomes fragrant.
Next, stir in beef broth and apple cider vinegar, scraping up any browned bits from the bottom of the pot. Then, stir in crushed tomatoes and bring the mixture to a simmer.
Return the brisket, fat side up, to the pot along with any collected juices from the pan. Then, sprinkle the herb mixture over the top of the brisket. Place the lid on the pot and transfer it to a 325°F oven for 3 hours.
After three hours, remove the pot from the oven. Arrange carrot pieces and baby gold potatoes around the brisket, making sure to submerge them in the braising liquid. Place the lid back on the pot and return the pot to the oven for one hour, or until the vegetables are fork-tender.
After roasting for four hours, remove the pot from the oven. Use a pair of tongs to transfer the carrots and potatoes to a large bowl, then cover the bowl with aluminum foil. Carefully lift the brisket out of the pot with two large spatula turners, place it on a large cutting board, cover with aluminum foil, and let it rest for 15 to 30 minutes before carving. Transfer the remaining sauce from the pot to a small saucepan, adjust the seasoning with salt and pepper, and keep warm until ready to serve.
Carve the brisket into slices, cutting against the grain, and serve with the reserved sauce on the side.
Yield 8 servings