Ingredients:

  • 3.5 lbs beef chuck roast, heavily marbled
  • 2 tbsp high-smoke point oil (avocado or grapeseed)
  • 1 tsp kosher salt
  • 1 tsp coarse black pepper
  • 3 large yellow onions, thinly sliced into half-moons
  • 4 cloves garlic, smashed and minced
  • 1 tbsp fresh thyme leaves
  • 2 bay leaves
  • 2 cups low-sodium beef broth
  • 1 packet (1 oz) French onion soup mix
  • 2 tbsp Worcestershire sauce
  • 1 tbsp balsamic vinegar
  • 2 tbsp cornstarch
  • 2 tbsp cold water

Instructions:

  1. Pat the beef chuck roast completely dry with paper towels. Season all sides aggressively with salt and pepper.
  2. Heat oil in a large cast-iron skillet over medium-high heat until wisps of smoke appear. Sear the roast for 5–6 minutes per side until a deep mahogany crust forms. Transfer the meat to the slow cooker.
  3. In the same skillet, sauté the sliced onions for 4-5 minutes to pick up the beef drippings. Add the minced garlic and thyme, cooking for 1 minute more until fragrant. Transfer onion mixture to the slow cooker.
  4. In a medium bowl, whisk together the beef broth, French onion soup mix, Worcestershire sauce, and balsamic vinegar. Pour the liquid over the beef and onions.
  5. Place the lid on the slow cooker and cook on Low for 8 hours until the beef is fork-tender.
  6. Remove the beef to a platter and tent with foil. Switch the slow cooker to High. Whisk the cornstarch and water to create a slurry and stir it into the cooking liquid. Whisk until the gravy thickens, then serve over the roast.