Lemon meringue pie

Method

1. First, make the pastry. Put the flour and butter in a food processor, then whizz until the mixture resembles breadcrumbs, or rub together in a mixing bowl with your fingertips. Pulse or mix in the 2 tbsp caster sugar with a pinch of salt. Mix one of the egg yolks with the water in a small bowl, then add to the mixture and pulse or mix until it forms a dough. Transfer to a lightly floured surface and knead very briefly, then shape into a disc, wrap in cling film and chill for 30 minutes. Preheat the oven to 190°C/fan170°C/gas 5 and put a baking sheet inside.
2. Remove the pastry from the fridge and roll out on a lightly floured surface to the thickness of a £1 coin. Use it to line a 23cm diameter x 3.5cm deep fluted loose bottomed tart tin. Roll a rolling pin over the top to remove the excess pastry (see picture A). Gently press the pastry into the fluted sides so it rises above the edge of the tin, then curl it over slightly to secure the pastry to the tin. Brush out any excess flour, then chill for 15 minutes or freeze for 10 minutes.
3. Line the chilled pastry case with foil or baking paper, then fill with baking beans or rice and blind bake on the hot baking sheet for 15-20 minutes. Remove the beans/rice and foil/baking paper, then return the case to the oven for 5-10 minutes until evenly sandy-coloured. If the base starts to puff up, prick it a few times with a fork. Brush the remaining egg yolk all over the pastry, working it into any cracks or holes, then bake for another 5 minutes. Set aside to cool. Turn the oven down to 180°C/fan160°C/gas 4.
4. For the filling, mix the 4 tbsp cornflour, 300g sugar and the zests in a large heavy-based pan. Stir in the juices with 50g cold water, then cook over a medium heat, mixing with a balloon whisk, until thick and smooth. When it starts to bubble, take it off the heat and whisk in the butter until melted. Whisk in the yolks and the whole egg, then return the mixture to the heat, whisking, for 5-10 minutes until it can thickly coat the back of the spoon (see tip). Set aside.
5. For the meringue, put the egg whites in a large clean bowl and whisk briefly with an electric hand mixer until foamy. Add the icing sugar and whisk briefly to combine. Set the bowl over a pan of simmering water (but not touching the water). Whisk until you have a thick, stable meringue – it shouldn’t move at all when you tip the bowl. Remove from the heat and whisk in the cornflour until smooth, then leave to cool a little.
6. Reheat the filling until steaming and pourable, then pour into the pastry case and smooth the surface. Gently spoon some of the meringue on top around the edges and spread it with a palette knife to just cover the pastry. Carefully smooth it into the centre to cover the filling, then spoon the rest on top in peaks and swirls.
7. Bake for 25-30 minutes until the meringue is beginning to brown, then remove and cool in the tin for 30 minutes. Carefully remove the pie from the tin and cool on a wire rack for at least 3 hours before serving. It’s best eaten the same day.