This go-to shredded beef recipe is quick and easy to prepare. Let it cook in the crockpot, and then divide it into 2-cup portions to freeze for use in other meals, such as Philly Shredded Beef Sandwiches (see associated recipe).
Trim fat from meat. If necessary, cut the roast to fit into a 4- to 5-quart slow cooker. Place onions and garlic in the cooker. Top with the roast. Combine broth, Worcestershire sauce, mustard, thyme, salt, and cayenne pepper in a medium bowl. Pour over everything in the cooker.
Cover and cook on Low for 11 to 12 hours or on High for 5½ to 6 hours.
Remove the meat from the cooker; remove the onions with a slotted spoon, reserving the cooking liquid. Using two forks, shred the meat; discard fat. Skim the fat from liquid. Add the onions to the meat; add enough liquid to the meat to moisten. Place 2-cup portions of the beef in airtight containers; cover and refrigerate for up to 3 days or freeze for up to 3 months.