Lemon meringue pie

Heat oven to 180°C/Gas Mark 4. Place the flour, sugar, butter and lemon zest in a food processor and pulse until you have a crumb-like mixture. Add 2 tbsp lemon juice and 1 tbsp cold water and pulse to bring the mixture together – if it's a little dry add more water 1 tsp at a time until you have a firm, smooth dough. Wrap the dough in clingfilm and place in the fridge for 20 minutes.

On a lightly floured surface, roll out the pastry into a round, the thickness of a £1 coin. Use to line a 22-23cm (8½-9in) fluted tart tin, pressing into the sides, then trim off the excess pastry. Prick the base with a fork, line with baking paper and fill with baking beans. Place the tin onto a baking sheet and bake for 20 minutes until the pastry is firm. Remove the beans and paper and return to the oven for 5 minutes until pastry is a pale golden colour.

Put the cornflour, caster sugar and lemon zest in a medium saucepan. Add the lemon juice, 175ml (6fl oz) cold water and butter. Gently bring the mixture to a boil, stirring constantly until thickened and smooth. Remove from the heat, leave for 1 minute, then whisk in the yolks and whole egg. Pour immediately into the pastry case.

Place the egg whites in a clean large bowl, then whisk on high speed until they form soft peaks. Add a quarter of the sugar and whisk until thick and smooth – continue adding the sugar in quarter batches until it has all been used and you have thick glossy peaks when the beaters are lifted out. Add the cornflour and whisk for a few seconds to incorporate.

Spoon teaspoonfuls onto the lemon filling, dropping randomly over the surface until covered – this helps to distribute the meringue evenly. Add the remaining meringue in larger dollops, leaving as many peaks as possible.

Place in the oven for 18-20 minutes, until the meringue feels crisp and is golden. Remove from the oven and leave for at least 30 minutes before slicing.