Generously season brisket with about 2 tsp salt and 1 tsp black pepper.

Heat large heavy skillet or cast iron pan over high heat. Add 1 Tbsp oil and when hot, add brisket (fat side down). Sear 4-5 min per side or until browned on both sides. Transfer to slow cooker, fat side facing up.

In the same pan, add 1 Tbsp oil and sliced onions and mushrooms. Sautee 5-7 min or until onions are caramelized and mushrooms softened. Place onions and mushrooms into the slow cooker and sprinkle chopped garlic over the top.

Combine chicken broth with Worcestershire sauce and pour mixture over meat.

Cover and cook on low 7 to 8 hrs or until cooked through and easy to pull apart with forks. Turn off slow cooker and rest 15 min with the lid on. Remove and discard excess fat then pull the beef apart with forks and keep it in the slow cooker to soak up the juices which will add amazing flavor and keep meat tender. Serve beef brisket and mushrooms, spooning slow cooker juices over the top.