Set the roast on the counter for 30 minutes before preparing.Trim some of the excess fat from the roast and Preheat the oven to 325 F.
Combine salt and pepper, 2 tbsp arrowoot starch, and the dried herbs in a bowl. Mix well and add the chuck roast, seasoning on all sides.
Using a large dutch oven, heat the avocado oil over medium heat. Once the oil is shimmering, add the chuck roast. Sear on all sides to lightly brown. Set aside.
Add the vinegar and scrape the bottom of the pan to pull up and burnt on bits of chuck roast.
Reduce the heat to medium-low and add the sliced onion and shallot. Lightly season with salt and pepper, sauteeing for 3-4 minutes.
Add the chuck roast back to the pot along with the broth, whole garlic cloves, and herb bundle. Place the lid on the pot and transfer to the oven.
Allow to cook in the oven for 3.5 - 4 hours, or until the meat easily shreds. Start to check the meat at around 2.5-3 hours! Remove from the oven once cooked. Remove the herb bundle and use a fork to smash the garlic.
Whisk 2 tbsp of arrowroot starch with about 3 tbsp of water (or beef broth) and add it to the pot roast, stirring it into the liquid to thicken. Allow to rest for 10-15 minutes before shredded.
If desired, turn the heat up to 400 F on the oven and return the meat to the oven. Allow to crisp for 5 minutes.
Serve topped with fresh chopped parsley and sides of your choice like rice, and vegetables!