Preheat oven to 300 F.
Heat a large dutch oven on the stove top over medium-high heat. Once hot, add avocado oil.
Pat the chuck roast dry with a paper towel.
In a small bowl, combine the cornstarch and seasonings together and mix well. Season the entire chuck roast on both sides.
Add to the hot dutch oven and sear for 5-8 minutes on each side until browned and a nice crisp crust forms. Transfer to a plate and set aside.
In the same dutch oven, reduce the heat to medium, then add the onions and minced garlic. Sauté for 2-3 minutes just until fragrant.
Add a big splash of beef broth and deglaze the pan by scraping the fond from the bottom of the pan with a wooden spoon. This helps to make the broth/gravy more flavorful.
Add the remaining beef broth, tomato paste, brown sugar, Worcestershire sauce, fresh thyme and rosemary, and bay leaves. Stir to combine. Then bring the dutch oven to a boil.
Once the dutch oven is boiling, transfer the seared roast back into the pot and cover with a lid. Place in the preheated oven and bake covered for 3 hours.
Remove from the oven and add the potatoes and carrots to the dutch oven. Cover with a lid and then return to the oven to cook for an additional 30 minutes, or until the meat falls apart and potatoes reach desired tenderness.
Plate and garnish with fresh herbs. Serve as is or with a side of crusty bread, rice, or quinoa if desired. Enjoy!