Passion fruit works so well with the lemon, intensifying the tangy flavour.
Sweet shortcrust pastry:
Place the flour, sugar and butter in a food processor and whiz briefly. Add half the beaten egg and continue to whiz. You might add a little more egg, but not too much as the mixture should be just moist enough to come together. If making by hand, rub the butter into the flour (1) until it resembles coarse breadcrumbs (2) then, using your hands, add just enough egg to bring it together (3). With your hands, flatten out the ball of dough until it is about 2cm (3/4in) thick (4), then wrap in cling film or place in a plastic bag (5) and leave in the fridge for at least 30 minutes or, if you are pushed for time, in the freezer for 10–15 minutes.
Make the pastry as described below, leaving to chill for 30 minutes before using.
Preheat the oven to 180°C (350°F), Gas mark 4. Line a 23cm (9in) tart tin and bake ‘blind’.
For the filling, cut the passion fruit in half and, using a teaspoon, scoop out the pulp from the centre and push through a sieve, reserving the seeds in the sieve for later.
Place the eggs, egg yolk, lemon zest and sugar in a bowl and whisk for a couple of minutes until the egg is all broken up.
Add the cream, lemon and orange juice and the strained juice from the two passion fruit. Mix well, skimming off any froth from the top of the mixture.
Carefully pour the filling into the cooked pastry case so it does not spill (sometimes I pour in the filling when it is sitting on a rack in the oven to avoid spilling it).
Clean about ten of the passion fruit seeds by removing them from the membrane that surrounds them and put to one side.
Reduce the oven temperature to 160°C (325ºF), Gas mark 3 and bake for 20 minutes, then place the passion fruit seeds on top. Bake for another 5–15 minutes or until the filling has just set in the centre – it should only wobble very slightly when you take it out of the oven.
Remove from the oven and allow to cool for about 15 minutes before removing the tart from the tin and transferring to a plate or cake stand. When it is cool, dredge a little icing sugar over the top and cut into slices to serve.