• Prepare Onions: Carefully slice onions evenly about ⅛ to ¼ inch with a mandolin or a sharp knife.

Oven Method

• Preheat Oven: Arrange a rack in the center of the oven; preheat the oven to 325℉.
• Season Roast: Season beef on both sides with 2 teaspoons of Kinder's cowboy butter seasoning mix.
• Sear Roast: In a large, high-sided, enameled cast-iron, cast iron, or stainless steel skillet over medium heat, heat 1 Tbsp. oil, to coat the pan. Sear beef until just browned, 3 to 4 minutes per side. Transfer to a plate.
• Caramelize the Onions: In the same skillet, over medium heat, heat butter. Add onions breaking them apart from the rings with spatula; season with remaining kinders seasoning, brown sugar, and 2 teaspoons of the beefy onion mix. Cook, stirring occasionally, until onions are golden brown and caramelize, about 9 -12 minutes. During the last 2 minutes add in the minced garlic.
• Layers: Add worcestershire, red wine and 1 ½ cups beef broth and stir until combined. Return roast and any juices to the skillet.
• Sprinkle the remaining beefy french onion packet, brown gravy packet, and black pepper on top of the roast and onions and then add thyme sprigs on top of both. Cover the skillet with a lid or foil and place in the oven.
• Cook roast beef, basting about halfway through and adding ½ to 1 cup of beef broth if needed, until meat easily pulls apart with a fork, about 2 hours and 45 minutes to 3 hours.
• Transfer the roast to a cutting board. Remove and discard thyme. Return the skillet to medium heat and bring the sauce to a simmer. Cook, stirring occasionally and skimming fat off the surface with a ladle, until the liquid is a desired consistency (additional broth or water can be added). Shred the beef into large pieces with a fork and return to the skillet.
• Heat the broiler to high heat. Top the roast with cheese. Broil, watching closely, until cheese is melted and starting to brown in spots, about 4 - 5 minutes.
• Serve with sliced toasted baguette.

Slow Cooker Instructions

• Sear the Beef: Start by seasoning your chuck roast with the steak seasoning. In a skillet over medium heat, heat the oil and sear the roast on all sides until nicely browned—about 3–4 minutes per side. This step adds tons of flavor, but you can skip it if you want.
• Caramelize the Onions: In the same skillet, melt the butter. Add the onions, season with the remaining steak seasoning, brown sugar, and 2 teaspoons of the beefy onion mix. Cook for about 9–12 minutes, stirring occasionally, until they’re golden and soft. Add the garlic in the last 2 minutes of cooking.

  If you don't want to caramelize the onions, you can add all the above ingredients to the bottom of the slow cooker instead.
• Layer in the Slow Cooker: Transfer the caramelized onions to the bottom of your slow cooker.

  Add Worcestershire, wine, and 1½ cups of beef broth. Place the seared roast on top. Sprinkle the rest of the soup mix, the gravy packet, and black pepper over the top. Nestle the thyme sprigs on top of the roast and around the onions.
• Slow Cook: Cover and cook on low for 8–9 hours or high for 4–5 hours, until the beef is tender and pulls apart easily with a fork.
• Thicken the Sauce (Optional): Once the roast is done, remove it from the slow cooker to a rimmed baking sheet or an oven-safe dish and remove thyme sprigs. In a cup or measuring cup, make a cornstarch slurry (2 tablespoons cornstarch + 1/4 cup water). Then pour the slurry into the liquid in the slow cooker to thicken while shredding the roast.

  You can also pour the juices into a saucepan and simmer on the stove for a few minutes to reduce, skimming any fat off the top if needed.
• Shred and Broil: Shred the beef into large chunks and return it to the sauce. Top with shredded cheese and broil for 4–5 minutes, just until the cheese is melted and bubbly