In a saucepan, combine beef broth, Worcestershire sauce, minced garlic, dried thyme, and black pepper. Bring to a simmer over medium heat and let cook for 15 minutes.

In a skillet, heat olive oil over medium-high heat. Add the thinly sliced roast beef and cook until warmed through, about 5 minutes.

Slice the French rolls in half. Place a portion of the warm roast beef on each roll. If desired, top with a slice of provolone cheese.

Serve the sandwiches with a small bowl of the au jus for dipping.