Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.

In a skillet, cook the ground beef over medium heat until browned. Add the chopped onion, salt, pepper, thyme, and parsley. Cook for another 5 minutes until the onions are soft. Remove from heat and let it cool slightly.

Roll out the puff pastry sheets on a floured surface and cut each sheet into 4 equal squares.

Spoon the meat filling onto four of the pastry squares, leaving a border around the edges. Top each with another pastry square and press the edges together to seal. You can crimp the edges with a fork for a decorative touch.

Place the pastry on the prepared baking sheet. Brush the tops of the pastries with the beaten egg for a golden finish.

Bake in the preheated oven for about 20-25 minutes, or until the pastry is puffed and golden brown.

Serve warm and enjoy.