For the wontons
For the filling
Preheat the oven to 210°C/425°F/Gas mark 7. Lightly grease a baking tray.
Roll the pastry on a lightly floured work surface to a rectangle about 45 x 35cm/18 x 14in. Cut out 12 rounds measuring 10cm/4in.
To make the apple filling, mix together the ingredients in a mixing bowl.
Divide the filling among the pastry rounds, then brush the edges with water. Fold the pastry in half to make a half-moon, and pinch the edges firmly together to seal. Brush the tops with egg white, and dust with caster sugar. Make 2 small slits in the top of each turnover. Bake for 15 minutes, then reduce the temperature to 190°C/375°F/Gas mark 5 and bake for a further 10 minutes. Serve warm.