2) Dump the dough onto a surface dusted with flour and shape into a flat disk. Press pastry into a 25cm round or 23cm square false-bottom pie tin, making sure that the finished edge is flat. Chill until firm.
3) Meanwhile, preheat the oven to 180°C/gas mark 4. Butter one side of a square of foil to fit inside the chilled tart case and place it, buttered side down, on the pastry. Fill with dried beans or rice.
4) Bake for 20 minutes. Remove the foil and beans, prick the tart all over with a fork and bake for 20 to 25 minutes more, or until lightly browned. Allow to cool to room temperature.
For the lemon curd filling:
1) Remove the zest of the lemons with a vegetable peeler or zester, being careful to avoid the white pith. Squeeze the lemons to make 125ml of juice and set the juice aside.
2) Put the zest in a food processor fitted with a steel blade. Add the sugar and process for 2 to 3 minutes, until the zest is very finely minced.
3) In the bowl of an electric mixer fitted with a paddle attachment, cream the butter with the sugar and lemon zest. Add the eggs, one at a time, and then add the lemon juice and salt. Mix until combined.
4) Pour the mixture into a medium saucepan and cook over low heat, stirring constantly, until thickened, about 10 minutes. The lemon curd will thicken at about 68°C or just below a simmer. Remove from the heat.
5) Fill the tart shell with the warm lemon curd and allow to set at room temperature.