Rub together the butter and flour until it becomes a sandy or fine breadcrumb texture.
Add the egg and sugar. Mix well.
Add a little water at a time until the mixture comes together into a soft dough. be careful not to overwork it at this stage.
Wrap the pastry and chill in the fridge for 30 mins.
Melt the butter and sugar together in a saucepan on low-medium heat.
Add the lemon juice and quickly whisk in the eggs. Go quickly so that the eggs don't scramble.
Return the mixture to the heat and cook slowly, stirring continuously, until the mixture thickens.
Leave to cool.
Roll out the pastry to the thickness of a pound coin and carefully line the pie dishes, taking care to push it into the corner between the base and sides. I've used crumpet rings, but loose-bottomed tins would work best.
Trim off any excess pastry. This can be tidied up after baking too.
Line the cases with non-stick baking paper and fill with ceramic baking beans (you could use uncooked rice if you don't have baking beans).
Bake for 20 minutes at 180c.
Whisk the two egg whites with a hand whisk until they form soft peaks.
Add the cornflour and sugar and whisk until the mixture becomes stiff peaks.
Remove the baking beans and baking paper from the pie cases. You can tidy up any pastry edges at this point with a sharp knife, but I quite like the rustic homemade look.
Spread a good layer of lemon curd over the base of each pie.
Add the meringue, then return to the oven for 15 minutes until crisp and golden on top.
Servings 4