600g/1lb 5oz Bramley cooking apples, peeled, cored, sliced
1 lemon, zest only
400g/14oz plain flour, plus extra rolling
5oz golden caster sugar, plus 1 tbsp for sprinkling
2 tbsp caster sugar
1 tsp ground cinnamon
2 tbsp cornflour
250g/10oz cold butter, cut into cubes
1 free-range egg, beaten with 2 tbsp cold water, plus 1 free-range egg, beaten, to glaze