Rough puff mascarpone tart with boozy peaches

Method

1. Put the cream in a saucepan over a low-medium heat until it reaches 80°C on the thermometer. Simmer gently for 2 minutes, then add the lemon juice and cook for another 3-4 minutes – it should start to thicken. Remove from the heat and leave to cool to room temperature.
2. Line a sieve with 2 squares of muslin so there’s plenty of overhang and set it over a mixing bowl. Spoon the cooled cream mixture into the centre, then fold over the overhanging muslin to cover. Put the bowl and sieve in the fridge overnight to drain. The mascarpone will be ready the next day.
3. To make the pastry, put the flour, sugar and salt in a medium mixing bowl. Make a well in the centre and grate in the frozen butter, holding the butter with the foil so it doesn’t melt in the heat of your hands. Add 4 tbsp of the ice-cold water and mix with a table knife until the pastry starts to come together. Add another 2 tbsp cold water and keep mixing until it forms a dough. Don’t use your hands until it becomes too difficult to mix with the knife. Working quickly, shape the dough into a disc, wrap in cling film, then chill for 30 minutes.
4. Meanwhile, put all the ingredients for the peaches (apart from the peaches) in a small pan and heat until the sugar has dissolved. Pour into a mixing bowl and add the peaches, making sure they’re submerged in the liquid. Cover the bowl and marinate for 30 minutes.
5. Heat the oven to 200°C/180°C fan/gas 6. Roll out the dough on a lightly floured surface until it’s a rough 20cm x 30cm rectangle the thickness of a £1 coin. Put the pastry on a baking sheet lined with non-stick baking paper, then lightly score a 3cm border around the edges. Brush all over the pastry with the beaten egg and sprinkle a little sugar around the border. Bake for 15-20 minutes until golden and puffed. Take out of the oven, then gently push the centre back down with a fish slice and leave the pastry to cool completely.
6. Meanwhile, mix the mascarpone with a splash of cream to loosen it to spreading consistency, then beat in the icing sugar and lemon zest in a mixing bowl until well combined. Spread the mixture over the pastry base, inside the border. Drain the peaches, shaking off excess liquid (set aside 100ml of the marinade; discard the rest and the solids). Put the reserved marinade in a small pan and heat over a medium-high heat for 2-3 minutes until reduced by half and turning syrupy. Scatter the peaches over the tart along with a few sprigs of lemon thyme, then drizzle over some of the reduced marinade. Serve straightaway.