First, make the pastry. Sift the flour and custard powder into a large bowl, then rub in the butter with your fingertips, until mixture resembles breadcrumbs. Stir in the orange zest and caster sugar, then mix in enough of the ice-cold water to make a soft dough (you may not need all of it) Knead lightly, then wrap in cling film and chill in the fridge for 30 minutes.

For the filling, place the apples, sugar and jelly in a pan with a tight-fitting lid, add 2 tbsp water, cover and simmer for 10 minutes, until apples begin to soften and the sugar and jelly cubes hay( dissolved. Take off the heat and set aside to cool.

Preheat the oven to 200°C/400°F/Gas 6. Roll out two-thirds of the pastry and use it to line a 23 cm-wide, 4 cm-deep pie dish. Spoon the cooled apple mixture into the dish in an even layer

Roll out remaining pastry and cut into 1 cm-wide strips, long enough to cross the top of the pie. Brush the rim of the pastry case with the beaten egg, then arrange the pastry strips over the top of the pie about km apart, and press into place at the rim of the pastry case. Repeat across the other way to create a lattice effect

Brush the strips with beaten egg and sprinkle with sugar. Bake for 35 to 40 minutes, until the pastry is golden. Serve warm, with custard, cream or ice cream.