Ingredients:  

Pastry:
250g/9oz unsalted butter, softened
115g/4oz caster sugar
500ml/17½ fl oz plain flour
Filling:
9 eggs
675g/1 lb 8oz caster sugar
250ml/9fl oz freshly squeezed lemon juice (about 4 lemons)
250ml/9fl oz plain flour
Icing sugar, for dusting

Method:
1. To make the pastry cream the butter and caster sugar until pale. Add flour and make into a dough. Flatten with your hands and press into a 33x23cm baking dish. Put in the fridge for 10 mins.
2. Preheat the oven to 180°C.
3. Bake the pastry for 15 to 20 minutes, until very lightly browned. Remove from the oven, but leave the oven on.
4. To make the filling whisk together eggs, caster sugar, lemon juice and flour.
5. Pour the filling over the pastry base and bake for 30 to 35 minutes, until set. Let cool to room temperature. Cut into squares and dust with icing sugar.