Step 1: For optimum flavor, let the chuck roast rest at room temperature for an hour before cooking. Whenever you do remove it from the fridge, season it generously with the all purpose seasoning.
Step 2: Make beef broth with the bouillon and hot water. Then place the beef roast in the slow cooker, pour in the broth, and top with sliced onions. Cover and cook until fork-tender.
Step 3: Once done, remove the chuck roast from the Crock Pot and transfer to a plate. Shred the beef and then return to the slow cooker.