Shredded Beef Sandwiches (French Dip Style)

1. Season your chuck roast generously with salt and pepper.
2. Heat a high smoke point oil in a large oven-safe pot or Dutch oven over high heat. Sear the seasoned chuck roast on both sides until deeply browned. Remove the roast from the pan and set aside.
3. Add a bit more oil to the pan if needed, then add the roughly chopped carrots, celery, and quartered yellow onion. Cook over medium heat for 2-3 minutes, stirring occasionally.
4. Add the minced garlic and tomato paste to the pot and cook for approximately 1 minute, stirring to combine.
5. Deglaze the pan with the red wine, scraping up any browned bits from the bottom. Allow the alcohol to cook off for a few minutes.
6. Stir in the fresh thyme and Worcestershire sauce, along with additional salt and pepper to taste.
7. Return the seared chuck roast to the pot. Add enough beef stock to come up the roast about 3/4 of the way.
8. Cover the pot tightly and place it in a preheated 250°F (120°C) oven. Cook for 7-8 hours, or until the beef is fork-tender.
9. Once cooked, remove the pot from the oven and let the roast rest, still covered, for 30 minutes.
10. After resting, remove the beef from the pot and shred it using two forks.
11. While the beef is cooking or resting, prepare the sauce: In a small bowl, combine mayonnaise, horseradish, chives, and stone ground mustard. Season with salt and pepper to taste and mix well.
12. Serve the shredded beef on your favorite rolls or bread, topped with the prepared sauce. You can also warm some of the cooking liquid for dipping (au jus style).