Method

For the pastry:
1 Rub the flour and butter together until the mix resembles fine breadcrumbs. Add the salt, icing sugar and the egg and mix until the dough just comes together. Wrap the dough in clingfilm and chill in the fridge for at least 30 minutes.

2 Preheat the oven to 180 degrees, or 160 if using a fan oven. Grease six small tart tins (10cm in diameter) or one large tart tin (24cm in diameter). Divide the dough into six (if making individual tarts). Roll out on a lightly floured surface until you have a disc that is slightly larger than your tart tin, and press the pastry into the tin, leaving a little pastry hanging over the edge. Prick the base of each tart with a fork and place the tins in the fridge for 15 minutes to chill.

3 Line each tart with parchment paper and fill with baking beans or rice. Bake for 15 minutes, before removing the parchment and beans and continue to bake for a further five minutes, until lightly golden. Brush the tarts with egg yolk and return to the oven for two minutes. Remove from the oven and allow to cool slightly. Reduce the oven temperature to 110 degrees or 90 degrees fan.

For the filling:
1 Heat the cream in a small saucepan to a simmer. Whisk the remaining filling ingredients in a large bowl, and once simmering, pour the cream over the egg and passionfruit mix, whisking all the time. Pour the custard into a large jug.

2 Place the tarts back in the oven, and slowly fill each tart case up with custard. Bake for 35 minutes until just set with a very slight wobble in the centre. Remove from the oven and leave to cool completely.

For the topping:
Sprinkle the sugar over the top of the tarts and place each one under the grill for two to three minutes until the sugar has melted and is starting to blister. Serve immediately.