Nectarine rose tart

Method

1. For the pastry, cream the butter and sugar in a mixing bowl using a wooden spoon until slightly paler. Beat in the egg, lemon zest and vanilla extract, then add the flour and salt and bring together with the spoon into a dough. Flatten into a thick disc, cover with cling film and chill for an hour. (Or use a food processor: whizz the butter with the sugar, then whizz in the egg, lemon and vanilla. Add the flour and salt, then pulse to a dough.)
2. To make the pastry cream, warm the milk with the vanilla pod and seeds and half the sugar in a medium pan over a low-medium heat until steaming (don’t let it simmer/boil).
3. Get out a baking tray and sheet of cling film. Whisk the yolks and remaining sugar in a mixing bowl until the sugar has dissolved, then whisk in the flour and cornflour. Pour half the warm milk into the egg yolk mixture, whisk until just combined, then pour it back into the pan. Whisk for 5-7 minutes over a low heat until thickened. Remove the vanilla pod, then pour the mixture into the baking tray and cover with cling film touching the surface. Cool, then put in the fridge.
4. When the pastry has chilled, quickly roll it out to a £1 coin thickness on a lightly floured surface. Line the 23cm fluted tart tin with the pastry, pressing it well into the flutes. Roll a rolling pin over the top of the tart case to cut off the excess. Using your fingers, gently work the pastry up the sides of the tin so it stands just proud of the top. Chill the tart case for 30 minutes. Remove the pastry cream from the fridge and let it come back to room temperature. Heat the oven to 190°C/170°C fan/gas 5.
5. Prick the base of the tart case with a fork, then line it with foil and fill with baking beans/uncooked rice. Bake for 20 minutes or until the base starts to turn golden, then remove the foil. Brush the base with egg white, then bake for 5-10 minutes more until lightly golden and dry. Cool on a wire rack.
6. Remove the vanilla pod from the pastry cream, spoon it into a food processor, then pulse a few times until smooth. With the motor running, add the butter, a piece at a time, until incorporated (see tips). Spoon the mixture into the tart case and level the top.
7. Cut around the stone of each nectarine to give 4 quarters. Slice into very thin crescents, putting the pieces on kitchen paper, covered with more damp kitchen paper.
8. To fill the tart, put one nectarine slice, skin-side up, into the pastry cream against the edge of the pastry. Put the next piece beside it, slightly overlapping, and continue around the edge of the tart to complete a circle. Repeat in rings, working your way into the centre. When there’s only a small gap left, roll up a nectarine slice, then wrap it in 1-2 more slices until it’s big enough to plug the hole. Put it in the centre of the tart.
9. Put the gelatine leaf into a small bowl of cold water for 5 minutes. In a small saucepan, warm the apricot jam with ½ tbsp water until slightly runny. Drain and squeeze the gelatine, add it to the jam and stir until melted. Brush the glaze over the nectarines until covered. Chill in the fridge for 2 hours. Bring back to room temperature to serve.