Preheat your oven to 400°F (200°C).
Roll out the puff pastry on a lightly floured surface.
Cut the pastry into squares, roughly 4 inches each.
In a mixing bowl, combine sliced roast beef, Swiss cheese, Worcestershire sauce, garlic powder, salt, and pepper.
Place a spoonful of the beef mixture in the center of each pastry square.
Fold the pastry over the filling and press the edges to seal.
Place the sealed squares on a baking sheet lined with parchment paper.
Brush each square with the egg wash.
Bake for 20-25 minutes until golden brown.
While baking, heat beef broth in a saucepan until warm.
Serve the French Dip Squares with warm beef broth on the side for dipping.