Prepare and Sear the Meat: Cut the 2-pound chuck roast into three pieces. Season the meat generously with salt and pepper. Heat oil in a hot pan and sear all sides of the meat until browned. Halfway through the searing process, add the sliced onion to the pan and allow it to cook alongside the meat.
Create the Flavor Base: Once the meat is seared, remove it from the pan and set aside. Keep the onions in the pan and add 3 tablespoons of butter. When melted, add 2 tablespoons of minced garlic and cook until fragrant, about 30-60 seconds. Remove the pan from heat.
Set Up the Slow Cooker: Place the seared meat in the crockpot. Add the cooked onions and garlic mixture. Pour in 1-2 packets of au jus gravy mix, 2 cups of low sodium beef broth, and 2 tablespoons of Worcestershire sauce.
Slow Cook: Cover and cook on high for 4 hours or on low for 6-7 hours until the meat is tender and easily shreddable.
Prepare the Meat: Once cooked, remove the meat from the crockpot and shred it using two forks, discarding any fat pieces. The meat should be tender and pull apart easily.
Assemble the Grilled Cheese: Butter one side of each bread slice and sprinkle with salt-free garlic and herb seasoning. Place a slice butter-side down in a preheated pan over medium-high heat. Layer with Swiss cheese, a portion of the shredded meat, and provolone cheese. Top with another slice of bread, butter-side up.
Cook the Sandwich: Grill the sandwich until golden brown on both sides and the cheese is melted, flipping halfway through. This should take about 2-3 minutes per side.
Serve: Serve the grilled cheese sandwich with a small bowl of the remaining au jus from the crockpot for dipping.
