Sprinkle both sides of the chuck roast with salt and black pepper.
Heat the oil in a large skillet, then brown all sides of the chuck roast, approx. 5 minutes per side, then transfer the roast to the slow cooker.
Add the sliced onions; then add the beef broth and Worcestershire sauce.
Add the thyme sprigs to the broth.
Cover and set the slow cooker to low for 8 hours.
Remove the chuck roast to a plate and shred using a fork, then place it back into the slow cooker to mix with juices.
Serve as desired.
Notes
To serve with polenta simply make polenta according to package directions. Top with the cooked, shredded chuck roast and its juices. Sprinkle with Parmesan cheese over top.You can also add in carrots and potatoes when adding in the beef broth to make it a complete meal.Store covered in the refrigerator for up to 3 days or freeze for later use.