Remove the roast from the fridge and packaging. Pat dry with Paper Towel.
Prepare the Seasoning Mix
Mix the vinegar, oil and seasonings together and whisk until combined.
Prepare the Slow Cooker
Spray the Slow Cooker with Cooking Spray, Add the diced onion and garlic to the bottom. Turn the Slow Cooker to High or Low (Low will take 10 Hours, High with take 7)
Add Ingredients and Cook
Add Roast to the Slow cooker so that it sits in the middle of the slow cooker on top of the onions and garlic. Pour the Seasoning mixture on top of the beef. Cover the slow cooker with the lid and let cook. It is said that every time you open the lid of a slow cooker while it is on, you increase the cooking time by 30 minutes. SO don't do it 😆
Cook on Low The Roast Should Take 10 hours. If its not cooked, you can extend the cooking time by an additional hour or until it is falling apart.Cook on High - The Roast Should Take 6 Hours. If it is not cooked, you can extend the cooking time by an additional hour or until it is falling apart.It's important to note that Newer slow cookers cook at a high temperature than old ones. So, if your slow cooker was manufactured in the last 10 years you will likely have 1 hour less cooking time.
Pull the Beef
Cut off any cooking string that is on the roast. Discard. Using two forks, pull the beef until it is shredded into desired sized Pieces.
Notes
If you start with a frozen roast, increase cooking time by 1 hour.