Cooking Steps

• Sear the beef: Heat the olive oil in a large skillet over high-heat. Generously season both sides of the chuck roast with salt and pepper. Sear both sides of the roast undisturbed for 4-5 minutes on each side, until deeply golden brown. Transfer to the crock pot.
• Caramelize the onions: Reduce heat to medium and melt the butter in the same pan (without cleaning). Add the sliced onions and cook to caramelize for 15 minutes. Add the balsamic and garlic and continue to cook for 5 minutes. Pour in the wine and cook until it's reduced, 5 minutes.
• Slow cook: Transfer the onions to the crock pot with the beef. Pour in the broth and add the thyme and bay leaves. Close the lid and slow cook on low for 8-10 hours, until the beef easily falls apart with a fork.
• Toast the bread (optional): If using the baguette, preheat the oven to 500°F just before beef is ready. Drizzle with olive oil and bake on a sheet pan until golden brown, 5 minutes.
• Thicken and finish: When the beef is done, open the lid, remove the thyme and bay leaves, and shred the beef it with two forks. Stir together the cornstarch and water and stir it into the beef. Top with the toasted bread and sprinkle generously with cheese. Close the lid and cook on high for 5-10 minutes, until the cheese is melted and the beef is thickened.