Preheat your oven to 200°C (400°F).
Heat olive oil in a skillet over medium heat.
Add the diced onion and sauté for 3-4 minutes until softened and slightly caramelized.
Add the ground pork to the skillet and cook until browned, breaking it up with a spoon as it cooks (about 5-7 minutes).
Stir in the diced apple, thyme, nutmeg, salt, and pepper. Cook for an additional 2-3 minutes until the apples soften slightly.
Remove the filling from heat and set aside to cool.
Roll out the puff pastry on a lightly floured surface. Cut into 4 equal squares.
Place a spoonful of the pork and apple mixture in the center of each pastry square.
Fold the pastry over the filling to create a triangle or rectangle shape, pressing the edges to seal.
Place the turnovers on a baking sheet lined with parchment paper.
Brush the tops of the turnovers with the beaten egg to give them a golden finish.
Bake for 15-20 minutes, or until the turnovers are puffed and golden brown.
Allow to cool slightly before serving. Enjoy!