• Season both sides of the chuck roast with salt & pepper. Heat the pan/skillet medium-high. Drizzle the bottom with olive oil and wait until it becomes hot. Then place the beef in the dutch oven/skillet and sear 4-5 minutes per-side or until browned. Remove the beef and set aside.
• In a the same pan: add butter and wait until it is nearly melted. Add sliced onions into the pan/skillet and mix. Cook for 5-8 minutes or until mostly caramelized. Add minced garlic and cook for 30-60 seconds or until fragrant. Pour in dry sherry; (using a wooden spoon) deglaze the bits and pieces on the bottom of the pan. Then, transfer to the slow cooker.
• Add seared roast to the slow cooker. Add beef broth, Worcestershire, soy sauce, thyme and bay leaves.
• Cook on low for 8-10 hours or high for 5-6 hours or until fork tender.
• Discard the bay leaves. Remove the roast and place in a medium-large sized bowl. Using 2 forks, shred the meat. Cover with aluminum foil until ready to eat. 
• Set the slow cooker to high. In a small bowl: combine cornstarch and water, mix until the cornstarch is fully dissolved. Add cornstarch mixture to the slow cooker and simmer for 20 minutes or until desired consistency. Season with salt & pepper to taste.
• Optional: pour about 1 cup of broth over the shredded beef and mix.
• Toast Bread - Preheat the oven to 300°F (148°C). Slice the bread in half (vertically). Spread melted butter on the inside of the bread. Lay the bread butterside down on a baking pan. Bake for 2-3 minutes. Remove bread from the oven.
• Prepare Sandwich - Place some of the dip in a small serving bowl. Place the shredded meat on top of the bread (bottom half). Top with caramelize onions & cheese. Put the top half of bread on the sandwich.

Serve immediately and enjoy!