Pat beef dry and season with salt and pepper on all sides.Heat olive oil in a skillet and sear beef until browned on all sides.Transfer beef to slow cooker and add onions and garlic to the skillet.Stir in tomato paste, then add broth and Worcestershire sauce, scraping the pan.Pour mixture over beef and add remaining seasonings and bay leaf.Cook on low for 8 hours or high for 5 hours until tender.Shred beef, return to juices, and rest 10 minutes before serving.