To make the pastry, put the flour, sugar and butter in a food processor and blitz on the pulse setting until the mixture resembles breadcrumbs. With the motor running, add the egg and process until the mixture is just beginning to come together in a ball.

Remove and shape into a slightly flattened ball. If you prefer to make your pastry by hand, see xxx

Preheat the oven to 200°C/Fan 180°C/Gas 6. Roll out the pastry on a lightly floured surface until it is about 25cm in diameter and slightly thicker than a £1 coin. Use the pastry to line your pie plate. Crimp the edges decoratively and chill for 30 minutes.

Toss three-quarters of the blackcurrants with the cornflour and all but a tablespoon of the sugar. Scatter over the centre of the pastry, then top with the remaining blackcurrants. Sprinkle both the pastry and the blackcurrants with the remaining sugar.

Bake for 25-30 minutes or until the blackcurrants are softened and the pastry is cooked and lightly browned.

Remove the tart from the oven and leave to stand for 10 minutes.

Top with spoonfuls of the crème fraiche and serve immediately, decorated with fresh mint leaves. Alternatively, leave until the tart cools and the crème fraiche sets, then scatter mint leaves on top and serve cold.