Deep-dish blueberry and peach pie

Method

1. First make the pastry. Put the flour and salt in a large bowl, then add the butter and rub together with your fingertips until the mixture resembles fine breadcrumbs (you could also do this part in a food processor). Stir in the icing sugar. Whisk the egg yolk with 2 tbsp ice-cold water and the lemon juice. Quickly stir this into the flour mixture with a table knife. If it seems a little dry, add a little more ice-cold water (the dough will come together when lightly kneaded so don’t add too much water as this will leave you with a tough pastry). Bring the dough together with your hands, turn out onto the worktop and knead very briefly to avoid overworking the pastry. Pull off a third of the dough, form both pieces into discs, then wrap well and chill for 2 hours (see Make Ahead).
2. Meanwhile, toss all the ingredients for the filling in a large bowl, then set aside for 30 minutes. Once the pastry has chilled, roll the larger piece of dough on a lightly dusted worktop into a roughly 30cm circle. Use this to line the pie dish, leaving some overhang. Fill with the blueberry filling. Roll out the remaining pastry to the same size as your dish, cut out 8 strips, then arrange in a lattice on top of the filling (see Know How). Press around the edges of the pie to join the lattice strips to the base, then trim any overhang and crimp the edges.
3. Heat the oven to 170°C fan/gas 5, putting a baking sheet in the oven as you do so to warm up (see Know How). Brush the pastry with the beaten egg, then sprinkle with the demerara sugar. Chill in the freezer for 10 minutes (or in the fridge for 20-30 minutes), then transfer the pie directly onto the hot baking sheet in the oven and bake for 50 minutes or until the pastry is golden brown. Leave the pie to sit for 15 minutes or so, then serve with whipped cream or vanilla ice cream.