Preheat the oven to 160C/320F/Gas 2.
For the tart, mix the eggs, lemon zest and caster sugar in a clean bowl throughly, for a minute.
Gently mix in the cream, then the lemon juice and finally the desiccated coconut.
Pour into the pastry shell and bake until golden all over. This should take about 40 minutes.
Remove from the oven and leave for one hour to cool and firm up.
For the cream, let the mascarpone warm to room temperature before putting it into a bowl with the double cream and icing sugar.
Whip until it begins to thicken, then add the passion fruit pulp and beat until firm.
To serve, simply cut the coconut tart into wedges and place on a serving plate with a spoonful of the passion fruit cream.