On a large plate mix together flour, salt, and pepper. Dredge the chuck roast on both sides.

Heat olive oil, on medium high, in a large pan. Place chuck roast in the pan and brown on both sides. This takes about 3-4 minutes on each side. Transfer beef to slow cooker.

In the same pan sauté garlic and shallots until fragrant and shallots are translucent, about 3-4 minutes. Stir in beef broth and scrap up any brown bits left from the roast. Transfer to the slow cooker with the beef.

In a bowl, whisk together balsamic vinegar, Worcestershire sauce, and brown sugar. Pour over the roast. Flip the roast a couple times to make sure the beef, balsamic mixture, shallots, and garlic are all combined. Cook on high for 5 hours or low for 8-10. Mine cooked perfectly on high for 5 hours.

Removed roast from slow cooker and place in bowl or on a plate. Shred the meat. It should fall apart. Pour some of the leftover sauce onto the shredded beef. Add ¼ teaspoon of salt. Mix well and serve.