Grapefruit and Ginger Meringue Pie

Ingredients

For the pastry

• 250g (9oz) plain flour, plus extra for dusting
• 65g (2⅓oz) icing sugar
• ½ tsp salt
• 3 tsp ground ginger
• ½ tsp ground cinnamon
• 125g (4½oz) butter, chilled and cubed
• 2 large free-range egg yolks
• 1 small free-range egg, beaten

For the filling

• 2 pink grapefruit, juice and zest only
• 3 white grapefruit, juice and zest
• 1 red grapefruit, juice and zest
• 70g (2½oz) fresh root ginger, peeled and sliced
• 5 large free-range egg yolks
• 3 large free-range eggs
• 60g (2¼oz) caster sugar
• 2 tbsp cornflour
• pinch salt
• 70g (2½oz) unsalted butter, cubed

For the Italian meringue

• 300g (10½oz) caster sugar
• 2 tsp lemon juice
• 140g (5oz) egg whites, at room temperature

Instructions

1. 1
   For the pastry, sift the flour, sugar, salt, ginger and cinnamon into a large bowl. Add the butter and, working quickly, rub the mixture together between your thumb and forefinger until the mixture resembles coarse breadcrumbs.
2. 2
   Add the yolks and 3 tablespoons water. Using your hands, mix to form a dough.
3. 3
   Turn onto a very lightly floured work surface. Gently and quickly knead the dough until it becomes smooth. Flatten the dough into a disc and wrap in cling film. Refrigerate for 30 minutes or freeze for 10 minutes.
4. 4
   Once the pastry has chilled, roll it out thinly on a lightly floured surface. Lift the dough into the tart tin and press into the edges. Leave any excess overhanging the sides of the tart tin. Prick the base with a fork and line with baking paper. Fill with baking beans or uncooked rice and chill again for 10 minutes.
5. 5
   Preheat the oven to 350F.
6. 6
   For the filling, add the juice and zest of the grapefruits to a large saucepan. Add the ginger and bring to the boil. Simmer for 10 minutes, then strain to remove the ginger and set the juice aside to cool.
7. 7
   In a separate heatproof bowl, add the yolks, eggs, sugar, cornflour and salt. Whisk to combine then set the bowl over a pan of gently simmering water (do not allow the water to touch the bowl). Pour in the grapefruit juice and whisk the mixture for about 15 minutes, or until it starts to thicken. Add the butter piece by piece, whisking all the time for about 15 minutes, or until the mixture is very thick. (If the mixture is taking too long to thicken, transfer the mixture to a pan and heat gently until thick.) Place some cling film on the surface of the curd to prevent a skin forming and set aside.
8. 8
   Remove the pastry from the fridge, place the tin on a baking tray and bake for 15 minutes. Remove the baking beans and greaseproof paper. Brush the base well with beaten egg and bake for another 7–10 minutes, or until the pastry is dry and pale golden-brown. Set aside to cool in the tin, then using a sharp knife cut away the overhanging edge.
9. 9
   For the Italian meringue, add the sugar and 180ml (6¼fl oz) water to a medium saucepan and bring to the boil.
10. 10
    While the sugar and water is being heated, use a paper towel to rub the inside of the bowl of a freestanding mixer with the lemon juice (this will remove any traces of grease that can cause meringues to fail). Add the egg whites to the bowl and whisk on a medium speed until stiff peaks form when the whisk is removed.
11. 11
    Once the sugar syrup has reached 230F on a sugar thermometer, remove it from the heat. With the motor running on the mixer, pour the syrup slowly down the side of the bowl. Once the syrup has all been added, increase the speed to high and whisk for about 7–9 minutes, or until the bowl is cool to the touch and the meringue has stiff peaks.
12. 12
    To assemble the tart, remove the cling film on the curd and gently reheat, if required. Once the curd is warm, pour into the pastry case and smooth the surface.
13. 13
    Spoon the meringue into a large piping bag fitted with a large open star nozzle. Pipe the meringue in swirls on top of the curd and then finish by browning the meringue with a chef’s blowtorch.
14. 14
    Serve while the filling is still warm.