Classic French Dip Sandwich with Rich Beef Au Jus

1.Prepare the Au Jus: In a medium saucepan, melt 1 tablespoon of butter over medium heat. Add the thinly sliced yellow onion and sauté for 8-10 minutes until deeply softened and lightly caramelized.

2.Add the minced garlic and cook for 1 minute until fragrant. Pour in the beef broth, water, dried thyme, Worcestershire sauce, black pepper, and salt.

3.Bring the mixture to a boil, then reduce the heat immediately to low and simmer, uncovered, for 40-45 minutes. This allows the flavors to deepen and the liquid to slightly reduce. Taste and adjust seasoning if necessary.

4.Preheat the oven to 180°C (350°F). Slice the baguettes lengthwise, being careful not to cut all the way through (creating a hinge). Spread the softened butter evenly on the cut sides of the bread.

5.Toast the bread: Place the buttered baguettes cut-side up on a baking sheet. Bake for 5-7 minutes until the bread is lightly golden and crisp. If using Provolone cheese, place two slices on the top half of each baguette and return to the oven for 1-2 minutes until the cheese is melted and bubbly.

6.Warm the Roast Beef: While the bread is toasting, gently warm the roast beef. You can either place the beef in a microwave-safe bowl and heat for 30-45 seconds, or briefly dip the slices into the simmering au jus (for about 10 seconds) to warm them through.

7.Assemble the Sandwiches: Pile the warm, tender roast beef generously onto the bottom half of the toasted baguettes. Close the sandwiches.

8.Strain the Au Jus: Pour the finished au jus through a fine-mesh sieve into a serving bowl or individual ramekins, discarding the solids (onions and garlic). Keep the au jus hot.

9.Serve immediately alongside the French Dip sandwiches for dipping.