How to Make It
Preheat the oven to 325°. In a large bowl, whisk the eggs with the granulated sugar and lemon zest until combined. Whisk in the lemon juice and 2 cups of the heavy cream, then stir in the coconut. Pour the filling into the tart shells. Bake the tarts for about 50 minutes, or until the filling is just set and the tops are deep golden around the edges. Transfer to racks and let cool.
In a bowl, combine the mascarpone with the remaining 1 cup of cream and the superfine sugar. Beat at medium speed just until the cream begins to thicken. Add the passion fruit pulp and beat until the cream is thick. Refrigerate until firm, at least 1 hour or overnight.
Cut the tarts into wedges and top with a dollop of the passion fruit cream. Spoon some passion fruit pulp over the cream and serve.
Passion fruit is available year-round at supermarkets. Look for heavy fruit with dimpled, deep purple skin.