Preheat the oven to 350°F/175°C.
Line a baking tray with baking paper.
Peel and dice your apple and put into a bowl. Add granulated sugar and cinnamon and mix till all apple pieces are coated.
Take your puff pastry squares, or, if you have a long sheet of puff pastry, cut 3 squares of 4 x 4 inch / 10 x 10 cm.
Add the apple mixture to a corner of each square.
Lightly brush the sides of the pastry with a little bit of water.
Turnover the empty part of the pastry over the apples. You should end up with a pastry triangle stuffed with apple.
Use a fork to seal the edges of the pastry.
Transfer the apple turnovers onto a baking tray lined with baking paper and brush them with egg.
Sprinkle with some cane sugar and put into the oven.
Bake for roughly 15-20 minutes, until golden brown.
You could also make smaller mini versions of these apple turnovers and make them bite size.
Add some homemade almond paste to give the recipe a nice twist.