Pat the brisket dry and sprinkle with the salt and pepper. Heat 1 tbsp of oil over medium-high heat in a Dutch oven or pot. Sear the brisket until it is browned, 4 to 5 minutes per side. Transfer the brisket to a plate.
Add the remaining 1 tbsp oil to the pot and cook the onion, stirring a few times, until softened, 3 to 5 minutes. Add the garlic and cook, stirring, for 1 minute. Add the tomato sauce, broth, Panda Brand™ Sweet & Sour Sauce, the raisins, peppercorns, and stir to mix well. Bring mixture to a boil, return brisket and any accumulated juices to the pot and transfer to the oven. Cook until the brisket is fork tender, 2 1/2 to 3 hours.
Remove the brisket from the oven, transfer the meat to a cutting board, and let it cool for 10 to 20 minutes. Serve.