The beauty of the blueberry filling in this pie is that when the pie is in the oven the blueberries collapse into the most delicious filling with a sticky thickened sauce. Its crying out for cold vanilla ice cream or thick cold cream.

For the filling place the blueberries, sugar, cornflour and lemon juice in a bowl and mix everything together. Set aside.

For the pastry place the flour in a bowl and add the butter and a pinch of sea salt and rub the butter into the flour until the mixture resembles breadcrumbs. Add the beaten egg to the mixture. Using a rounded blade knife mix the egg in until its starts to form a firm dough. Bring together with your hands to form a ball. Knead briefly then wrap in cling film and chill in the fridge for 30 minutes.

Grease a 23cm pie tin or dish. Remove the pastry from the fridge and bring to room temperature. Dust the work surface with plain flour and roll two thirds of the pastry out to 2mm thick and 2cm larger than your tin.

Transfer the pastry to your pie tin and gently press the pastry into the tin making sure it is even all the way round. Trim off any excess pastry with a knife. Gather up the remaining pastry pieces with the remaining third of pastry and roll out to 2mm thick and using a star cutter cut out stars for the top of the pie.

Preheat the oven to 180C/Fan 160C/gas 4. Place a baking tray in the centre of the oven to heat up.

Spoon the blueberry filling onto the pastry and then top with the stars around the edges, overlapping as you go round. Brush the pastry with the beaten egg to glaze. Place the pie on the hot baking tray and bake for 35 minutes until the pastry is cooked and golden and the filling is bubbling. Leave to cool before cutting into wedges and serving with cream or ice cream.