2 apples, peeled, cored and cut into 3cm/1ΒΌin chunks
1 lemon, juice only
plain flour, for dusting
50g/1ΒΎoz soft light brown sugar
1 tsp ground cinnamon
1 tbsp cornflour
2 tbsp demerara sugar
1 tsp ground ginger
2 tbsp unsalted butter
1 free-range egg, beaten
320g sheet ready-made puff pastry