Preheat the oven to 375 degrees F (190 degrees C). If making home-made pastry, roll out the pastry to line a 23 cm (9 inch) round loose-based fluted tart tin. Chill in the fridge for 20 minutes.
To make filling, whisk together eggs, egg yolks, and sugar. Add the cream, whisking all the time, and then the lemon juice and zest.
Line the pastry shell with a crumpled piece of baking paper and baking beads (use dried beans or rice if you do not have beads). Blind bake the pastry for 10 minutes, remove the paper and beads and bake for a further 3-5 minutes, or until pastry is just cooked but still pale. Remove from the oven and reduce the temperature to 300 degrees F (150 degrees C).
Put the tin on a baking tray and carefully pour the filling into the pastry case. Return to the oven for 35-40 minutes, or until the filling has set. Leave to cool completely before serving.