Persian saffron tart with passion fruit curd & mascarpone mousse

Method

1. For the saffron pastry, combine the flour, sugar and lemon zest in the bowl of a food processor and whiz to combine. Add the chopped butter and salt and pulse until it forms sandy crumbs. Add the egg yolk and saffron liquid and pulse until it just begins to come together. Tip onto a lightly floured work surface and knead briefly to bring it together into a ball of pastry. It is fairly stiff and crumbly, but don’t overwork it. Shape into a flattish disc, wrap in cling film and rest in the fridge for at least an hour. Alternatively, freeze until ready to use.
2. To make the mascarpone mousse, combine the sugar and water in a small pan and heat gently until the sugar dissolves. Once completely dissolved, increase the heat and cook, without stirring, for 6–7 minutes, or until it reaches the ‘soft ball’ stage, which is 120°C on a candy thermometer.
3. At the same time, combine the egg and egg yolk in the bowl of a stand-mixer and whisk vigorously for around 6–8 minutes, until very light and frothy. Turn off the motor.
4. Measure out 60 ml of the syrup. (Add the pulp from the 3 passion fruits to the remaining syrup and set this aside until ready to serve.) Pour the measured syrup into the whipped eggs carefully, taking care to avoid the sides of the bowl and the whisk attachment. Turn the motor on slowly, then increase the speed gradually to high and whisk until the mixture is cool – around 5 minutes.
5. Meanwhile, soak the gelatine leaf in a dish of cold water for a minute, until soft and slippery. Squeeze it to get rid of any excess water then mix it with 2 tablespoons of the cream. Zap in the microwave for 5 seconds and stir to dissolve it completely.
6. Whisk the remaining cream to medium peaks then set aside.
7. Use a balloon whisk to mix the mascarpone, vanilla extract and gelatine liquid together in a large bowl then pour in a little of the mousse and whisk gently to slacken. Fold in the rest of the mousse and then fold in the whipped cream and orange flower water. Chill in the fridge while you bake and then cool the tart shell.
8. When ready to bake the tart shell, butter a 33 cm x 10 cm rectangular tart tin. Place the chilled pastry on a lightly floured work surface and knead it briefly to a workable consistency. Roll the pastry, working fairly quickly so it doesn’t warm up too much. Try to keep it in a rectangular shape and roll to a thickness of about 3 mm. Use the rolling pin to lift the pastry carefully onto the prepared tart tin and use your fingers to press it in along the sides and edges, evenly and firmly, so there are no cracks. Don’t worry too much if it breaks. Fill any gaps with excess pastry and leave an excess edge all around to allow for shrinkage as the tart bakes. Transfer to the freezer for 30 minutes, or until very firm.
9. Meanwhile, preheat the oven to 180°C. Line the chilled tart shell with baking paper and fill with baking beans (or rice). Bake for 18 minutes, then carefully lift out the paper and beans. Return the tart shell to the oven for a further 5–10 minutes, or until the pastry is completely set and golden brown. Remove from the oven and set aside for around an hour to cool completely.
10. Spread the mascarpone mousse into the base of the cold tart shell, filling it about half full. Chill for 2 hours.
11. While the mousse is chilling, make the passion fruit curd. Whisk the eggs in a large bowl. Combine the flesh and seeds from the passion fruit and the sugar in a saucepan and heat gently to dissolve the sugar. Once dissolved, bring to the boil, then pour the hot mixture onto the eggs, whisking continuously. Tip the mixture back into the saucepan, and return to the heat, whisking all the time until it thickens. This should only take a few minutes. Remove from the heat.
12. Soak the gelatine in a dish of cold water for a minute, until soft and slippery. Squeeze it to get rid of any excess water and add to the passion fruit mixture, along with the lemon juice and butter. Whisk until the butter has completely melted. Push the curd through a sieve to remove the passion fruit seeds then set the curd aside for about 45 minutes until it cools to room temperature.
13. Spoon the cooled passion fruit curd into the tart shell, on top of the chilled mousse and spread the surface evenly. Leave to set for 2–3 hours, so that when you cut it into slices, the neat layers are maintained. Serve drizzled with the passion fruit syrup.