0 Preheat your oven or Traeger Grill to 350F.
1 Place the beef on a tray and generously season all sides with salt and pepper. For best results, transfer the beef to a refrigerator and let it sit, uncovered, for 4 to 6 hours. If you’re short on time you can cook it right away.
2 Preheat a Dutch oven over medium heat for 5 minutes. Raise the heat to medium-high, add 2 tablespoons of avocado oil and heat until the oil is shimmering. Carefully add the beef to the pot and cook until deeply browned, around 4 minutes. Flip and repeat the browning process on all sides, around 8 more minutes total. Transfer the browned beef to a tray and set aside.
3 To the pot, add the celery and onion, season with a pinch of salt and cook, lifting any brown bits off the bottom of the pot with a wooden spoon, until the onions are soft and translucent, around 4 minutes. Add the tomato paste and cook, stirring to incorporate, around 2 minutes. Add the garlic and cook, stirring, until fragrant, around 1 minute. Add the beef bone broth and cook, stirring and lifting any brown bits with a wooden spoon, until the liquid comes to a steady simmer.
4 Using butcher’s twine, make a bouquet garni by tying together the thyme, parsley and bay leaves. Add the bouquet garni to the pot along with the carrots and submerge them into the broth. Cover the pot with a tight-fitting lid, transfer to the oven or Traeger and cook, occasionally basting the beef with the gravy every hour, until the meat is very tender and almost falling apart, around 3.5 hours.
5 Once the meat is tender, remove the lid, add the potatoes and submerge them into the broth, raise the heat to 425F and cook until the potatoes are fork-tender, around 35 minutes.
6 Carefully transfer the beef, potatoes and carrots to a large serving platter, reserving all of the broth in the pot, and loosely tent with foil to keep warm. Place the pot over medium-high heat and bring the liquid to a steady simmer. In a small bowl, combine 2 teaspoons arrowroot starch with 2 teaspoons cold water and stir until dissolved to make a slurry. Add the slurry to the broth, stir to incorporate and cook, stirring regularly, until the gravy becomes thick enough to coat the back of a spoon, around 10 minutes. Taste the gravy for seasoning and adjust with salt and pepper as desired. Pour the gravy into a serving bowl and serve with the pot roast.
