Rub the brisket with salt, black pepper, garlic powder, smoked paprika, onion powder, and dried thyme. Let it sit for 10 minutes to absorb the flavors.
Heat a large skillet over medium-high heat. Sear the brisket on both sides for 3–4 minutes per side until golden brown. This step enhances the flavor and locks in the juices.
Place sliced onions at the bottom of the slow cooker. Lay the seared brisket on top. Pour beef broth and Worcestershire sauce over the brisket. Cover and cook on low for 8–10 hours or until the meat is tender and easily shreds with a fork.
Once done, remove the brisket from the slow cooker and let it rest for 10 minutes before slicing. This helps retain its juices.
Slice the brisket against the grain for maximum tenderness. Drizzle with the slow-cooked juices and serve with your favorite sides.