Sear the Beef: Heat olive oil in a skillet over medium-high heat. Sear beef chuck roast for 4-5 minutes on each side until browned.

Sauté the Aromatics: Add diced onion and sauté for 3-4 minutes until translucent. Add minced garlic and sauté for an additional minute.

Combine in the Slow Cooker: Transfer the onions and garlic to the slow cooker, placing the beef on top. Pour in beef broth and crushed tomatoes, and add Worcestershire sauce, oregano, thyme, salt, and pepper.

Slow Cook the Beef: Cover the slow cooker and cook on low for 8 hours until the beef is tender.

Shred the Beef: Remove beef from the slow cooker, shred it with forks, and mix it back into the gravy.

Serve on Toasted Bread: Toast slices of bread, spoon beef mixture onto each slice, top with cheese, and broil for 1-2 minutes until cheese melts.