Blackberry & pistachio tart

1 Preheat the oven to 170ºC, gas mark 3. Unroll the pastry onto a baking tray on its paper. Brush a 5cm border around the edges with beaten egg (set the remaining egg aside). Cut a 2cm strip from each side, then stick these back around the edges of the pastry to form a raised border; trim off any excess. Prick the centre of the pastry with a fork; chill until ready to use.

For the pistachio cream, put 80g of the pistachios in a food processor and whizz to a breadcrumb consistency. Add the rest of the beaten egg, the butter, 80g sugar, lemon zest, 1 tbsp corn flour and a pinch of salt. Keep whizzing until you get a well-combined paste. Spread all over the centre rectangle of the pastry.

In a bowl, mix ½ of the blackberries with the remaining 1 tbsp sugar and 1 tbsp corn flour, then scatter this mixture over the pistachio cream. Bake for 15 minutes, remove from the oven, top with the remaining berries and return to the oven for a final 10-15 minutes, until the pastry is golden and the pistachio cream is set. Roughly chop the remaining pistachios and sprinkle over the tart.