St Clement’s tart

Serves 8

150g chilled unsalted butter, cubed, plus extra for greasing 300g strong flour, plus extra for dusting 1 tbsp flaked sea salt 25g caster sugar 1 egg yolk 100ml cold water 300ml double cream 100g icing sugar zest and juice of 1 lemon, plus 1 whole lemon zest and juice of 1 orange, plus 1 whole orange airtight wrap 12 x 35cm rectangular, fluted, loose-bottomed tart tin baking paper baking beans mandoline slicer

In a large bowl, combine the butter cubes, flour, sea salt and caster sugar, then rub the butter into the dry ingredients for 2-3 mins, using fingers and thumbs, until the mixture resembles breadcrumbs. Mix in the egg yolk, then slowly stir in the cold water until a dough forms that can be kneaded together. Not all the water may be needed. Knead the dough with one hand in the bowl until it comes together into a ball, then wrap the ball in an airtight wrap and leave to chill for 1 hr.

Preheat the oven to 200°C/180°C fan/gas mark 6 and grease the oven tray. Dust a clean kitchen surface with the extra flour, then roll the pastry out to fit the tart tin. Line the tin with the pastry, then trim to neaten, a little above the top of the tin, and prick the bottom of the pastry with a fork a few times. Cover with baking paper and fill with baking beans. Bake for 10 mins, then remove the beans and paper. Bake for a further 10 mins until the tart case is dry and golden.

Place the double cream in a large mixing bowl and whisk with an electric whisk for 2-3 mins until thick. Fold in the icing sugar and the zest and juice of 1 lemon and 1 orange. Transfer the mixture to the tart case and smooth over to flatten.

Using the mandoline slicer, slice the remaining orange and lemon very thinly. Cover the filling with a layer of the slices. Leave to chill for 30 mins, then serve.