Preheat your oven to 400°F (200°C).
Roll out the puff pastry on a lightly floured surface.
Cut the pastry into squares, about 4 inches each.
In a bowl, combine the beef broth, Worcestershire sauce, and Dijon mustard.
Layer the beef, cheese, and a tablespoon of the sauce on each pastry square.
Fold the pastry squares over the filling and seal the edges.
Place the prepared squares on a baking sheet lined with parchment paper.
Bake for 20-25 minutes, or until golden brown.
While the squares bake, heat the remaining beef broth mixture in a saucepan.
Once baked, allow the squares to cool slightly before serving.