Posted for Potty Nigel Slater's recipe from The Kitchen Diaries. Use lemons as an alternative.
Make certain there are no cracks or holes in your pastry case before you pour the filling in. Serves 8.
170g plain flour
50g golden icing sugar
an egg yolk
1 tbsp cold water
for the filling:
6 large eggs
250g caster sugar
the juice of 5-7 limes (180ml)
175ml double cream
Put the flour and icing sugar into the bowl of a food processor, add the butter cut into chunks, and blitz for a few seconds. Stop when it resembles fine breadcrumbs. Mix in the egg yolk and the water. Tip into a mixing bowl and bring the dough together into a thick log with your hands. Wrap in greaseproof paper and refrigerate for half an hour.
Cut thin slices from the log of pastry, then press them into a loose-bottom 23-24cm tart tin with high sides (3.5cm), pressing the pastry gently up the sides and over the base. (It is too fragile to roll.) Make certain that there are no holes, otherwise the filling will leak through. Place a sheet of greaseproof paper into tart case and fill it with baking beans (I use old haricot beans, but you can buy ceramic or metal beans especially for the job from cookware shops). Bake the tart case for 10 minutes, then remove the greaseproof paper and bake for a further 5 until the pastry is dry to the touch.
Turn the oven down to 150C/gas mark 2. Finely grate the zest from two of the limes. Squeeze enough limes to get 180ml of juice (this depends on their ripeness). Mix the eggs and sugar, beating lightly for a few seconds - you don't want it to be frothy - then stir in the lime juice and cream. Pour through a sieve, then stir in the lime zest. Pour into the baked tart tin and bake for 45-50 minutes. Remove while the filling is wobbly. Leave to cool.