Best French Dip Sandwiches

Ingredients:

• 1 long French baguette
• 1 1/2 pounds (340g) rare roast beef, thinly sliced
• 3 tablespoons (42g) unsalted butter
• 1 teaspoon fresh thyme leaves, finely chopped
• 3 large yellow onions, peeled and thinly sliced
• 1/2 teaspoon salt
• 1/2 teaspoon black pepper
• 1/4 teaspoon red pepper flakes
• 1/2 cup (113ml) cooking sherry
• 2 cups (454ml) beef stock
• 1/2 teaspoon cornstarch
• 1 teaspoon water
• 10 ounces Gruyere cheese, grated
• Optional additions:
  • 2 cloves garlic, minced
  • 1 tablespoon Worcestershire sauce
  • 1 bay leaf

Instructions:

1. Prepare baguette: Slice baguette into 4 pieces. Slice each piece in half lengthwise, cutting 3/4 of the way through.
2. Preheat oven: Preheat oven to 500°F (260°C).
3. Assemble sandwiches: Divide roast beef evenly among bread pieces. Place each piece on a piece of aluminum foil.
4. Caramelize onions: In a large skillet, melt butter over medium heat. Add thyme and onions, stir to coat. Season with salt, pepper, and red pepper flakes. Cook, stirring occasionally, for 20-25 minutes, or until soft and golden.
5. Deglaze and simmer: Add garlic (optional) and cook for 1 minute. Stir in sherry and cook for 3-4 minutes, or until sherry is absorbed. Add beef stock, Worcestershire sauce (optional), and bay leaf (optional). Bring to a boil, then reduce heat to simmer and cook for 5 minutes.
6. Thicken au jus: Mix cornstarch with water to form a slurry, then add to the onion mixture. Cook for 1-2 minutes, until au jus thickens slightly.
7. Assemble sandwiches with toppings: Use a slotted spoon to scoop onions out of broth and place in a bowl. Divide au jus into individual ramekins. Divide Gruyere cheese and onions evenly on top of the roast beef in the sandwiches, placing the cheese on first, then the onions.
8. Wrap and bake: Wrap foil around each sandwich, place on a baking sheet, and bake for 5 minutes.
9. Serve: Carefully remove pan from oven, unwrap sandwiches, and serve immediately with au jus on the side.

Optional additions:

• For extra flavor: Add minced garlic during the onion caramelization process, Worcestershire sauce to the au jus, or a bay leaf for depth.
• For a richer au jus: Use beef bone broth instead of regular beef stock.
• For a spicier kick: Increase the amount of red pepper flakes or add a dash of hot sauce to the au jus.

Enjoy your delicious Roast Beef & Gruyere French Dip Sandwiches!