Lemon, pistachio and passion fruit tart

This year, Lu and I decided to stay in for New Year’s Eve.  I’m sure it’s a sign we’re getting old, but it was absolutely lovely to be at home, just the two of us, after all the hectic socialising over Christmas!  So we cooked a lovely meal for each other: Lu made Thai crab cakes to start, and for a main course we had sea bass with goose fat-roasted potatoes and I made an Asian mango salad to go with it.  This was the dessert – loosely based on a classic Tarte au Citron, I added toasted, ground pistachios to the filling and made a lemon and pistachio sweet pastry.  The whole thing was topped with lemon-infused whipped cream, passion fruit and ground caramelised pistachios.  This was a real show stopper of a dessert – and a very decadent breakfast on New Year’s Day before a walk in the sunshine to blow away the cobwebs! 

Ingredients

For the pastry

2 oz pistachios, toasted and finely ground

Zest of 1 lemon, finely grated

4 oz plain flour

3 ½oz cold butter, cut into small cubes

1 oz icing sugar

1 free-range egg yolk

1 tbsp cold water

For the filling

5 free-range eggs

4fl oz double cream

8oz caster sugar

4 lemons, juice and zest

For the caramelised pistachios

2 oz caster sugar

2 tbsp water

4 oz pistachios

For the lemon cream

250ml double cream

6 tbsp icing sugar

Juice of 1 lemon

To decorate

4 passion fruit, pulp and seeds
8 physalis fruit, leaves left on

Method

1. Begin by toasting the pistachios: heat the oven to 175°C, spread the nuts on a baking sheet and place in the oven for 8 to 10 minutes, shaking the sheet occasionally. Watch carefully as nuts burn quickly.  Set aside to cool.
2. To make the pastry, place the toasted pistachios in a food processor with the lemon zest, and blitz until finely ground. 
3. Add the flour, butter and icing sugar and pulse briefly until the mixture resembles breadcrumbs.
4. Add the egg yolk and water and pulse again until the mixture sticks together in clumps.  Tip the pastry onto a work surface and knead two or three times to make it smooth. 
5. Grease a 9 inch loose-bottomed, fluted tart tin.
6. Lay a piece of baking paper on the work surface, and place the loose base of the tart tin on it.  Draw a circle onto the paper about 1½ inches bigger than the tin base.  Leave the base on the paper and dust it with flour.
7. Place the pastry ball in the centre of the tin base and flatten it out slightly. Roll out the pastry, still on the base, until it meets the circle mark. As you are rolling out, turn the pastry by turning the paper.
8. Gently fold the pastry surrounding the tin base in towards the centre, and then carefully lift the tin base off the paper.  Drop the base into the tin, then ease the pastry into the corners and up the sides of the tin, pressing the overhang lightly over the rim. If the pastry has cracked at all, simply press it together to seal. Press the pastry into the flutes of the tin then lightly prick the base with a fork, but not quite all the way through.
9. Place the pastry-lined tin on a baking tray, cover loosely with cling film and chill in the fridge for 30 minutes. Preheat the oven to 200°C.
10. Meanwhile, make the caramelised pistachios: place the sugar and water in a small saucepan, heat to dissolve the sugar, and then add the pistachios.  Heat rapidly to caramelise the sugar, which should bubble up coating the pistachios.  Remove from the heat and pour onto a baking sheet to cool.  Once cooled, place transfer to a food processor and blitz until fairly coarsely ground.
11. Remove the cling film from the pastry case and line with foil so it supports the sides, then fill with baking beans. Bake blind for 12-15 minutes, until the pastry is set, then lift out the foil and beans.
12. Carefully trim the excess pastry from the sides using a sharp knife, then return the empty pastry case to the oven for another 10-12 minutes or until it is pale golden and completely dry. Set aside to cool while you make the filling. Reduce the oven temperature to 170°C.
13. To make the filling, break the eggs into a large bowl and whisk together with a wire whisk. Add the cream, sugar, lemon zest and juice and whisk again until they are all well combined.
14. Place a sieve over the bowl of filling, and sift in the ground caramelised pistachios.  Only the most finely ground nuts should make it through the mesh – set aside the more coarsely ground pieces, which you’ll use to decorate the tart.
15. Pour the filling mixture into a jug, then into the cooled baked pastry case. To prevent it spilling as it goes in the oven, pour in most of the filling so it almost fills the tart, carefully sit the baking sheet and tart on the oven shelf, then top up with the rest of the filling to completely fill it. Bake for about 30-35 minutes or until just set but with a slight wobble in the centre, and transfer to a wire rack to cool slightly.
16. When the pastry seems firm enough, remove the tart from the tin. The easiest way to do this is to place the base of the tin on an upturned can or jam jar and let the outer ring fall to the work surface. Transfer the tart to a serving plate to cool completely.
17. Make the lemon cream: beat the cream, icing sugar and lemon juice and thick. Once the tart is completely cool, spread the lemon cream on top with a palette knife, cover with the pulp and seeds of the passion fruit, sprinkle with the reserved coarsely ground caramelised pistachios and decorate with a few physalis fruit.

Adapted from Mary Berry’s Tarte au Citron