In a skillet over medium heat, sauté your choice of ground meat until thoroughly cooked, about 8-10 minutes. If adding vegetables, toss them in during the last few minutes, cooking until soft.

Preheat your oven to 400°F (200°C) while you prepare the pastry. On a lightly floured surface, roll out a sheet of puff pastry into a rectangle, about 1/4 inch thick.

Once your filling has cooled, place it in a line along one edge of the pastry. Sprinkle your cheese generously over the meat mixture, then carefully roll the pastry away from you, keeping it tight. Pinch the seams to seal the roll.

Transfer the rolled puff pastry onto a baking sheet lined with parchment paper. Whisk an egg in a bowl and brush it over the surface of the pastry.

Place the baking sheet in your preheated oven and bake for 25-30 minutes, or until the pastry is puffed and golden brown. Keep an eye on it to avoid over-browning.

Once baked, remove the roll from the oven and cool on a wire rack for about 5 minutes. Cut into thick pieces and serve warm with your choice of dipping sauce.