Martha Colllison's lemon & almond meringue pie

1. Preheat the oven to 180°C, gas mark 4. To make the pastry, place the flour, almonds, icing sugar and butter into a food processor, and pulse until the mixture resembles fine breadcrumbs.

2. Add the egg yolk and 1 tbsp of cold water, and pulse again. The mixture will clump together. Shape it into a flat disc using your hands, wrap in clingfilm (or clean reusable foodbag) and place in the fridge for 30 minutes.

3. Roll the chilled pastry out into a large circle just larger than a 20cm circular loose-bottomed tart tin. It should be around 0.5cm thick. Gently place into the tin, making sure you push the dough right into the edges, and prick the bottom with a fork. Place a layer of baking parchment over the top, fill with baking beans and bake for 25 minutes. After 15 minutes, remove the baking parchment and beans. Return to the oven for the remaining 10 minutes. Allow to cool while you make the filling.

4. Place the cornflour into a medium saucepan. Whisk in enough lemon juice to form a thin paste, then add the remaining juice and zest. Stir in the sugar. Heat the mixture on low for 2-3 minutes, whisking all the time, until slightly thickened and glossy.

5. Add the butter and egg yolks, and whisk vigorously to combine. Bring to the boil and cook for a further 2-3 minutes until thick – the mixture will have the consistency of crème pâtissière and should hold its shape when you lift out the whisk.

6. Roll out the marzipan into a disc that fits snugly into the base of the baked tart case. Press it into the tin, then top with the lemon filling, smoothing with a spatula.

7. To make the meringue topping, whisk the egg whites on high speed until they form soft peaks. Add the sugar a spoonful at a time, whisking well after each addition. Continue to whisk for a few minutes once all the sugar has been added. The mixture should be glossy and hold stiff peaks. Add the cornflour and mix to combine.

8. Spoon the meringue onto the set filling, using the back of a spoon to swirl it right into the edges of the pie. Sprinkle over the flaked almonds. Bake for 20 minutes, until the top is beginning to brown and feels crisp to the touch. Allow the pie to cool to room temperature before serving in generous portions. Store any leftovers in the fridge, where they will keep for 2-3 days.