Apple, rose and pistachio tarts

Method

1. For the pastry, whizz together the butter and icing sugar in a food processor until smooth. Add the egg yolk and whizz again until combined, then add the flour and pulse briefly until the pastry comes together to form a dough. Turn out onto a lightly floured surface and knead very gently to bring the pastry together. Shape into a rectangle, wrap well in cling film and chill for 30 minutes. (If you don’t have a food processor, cream the butter and sugar in a mixing bowl using a wooden spoon, then mix in the the egg yolk and flour, shape and chill as above.)
2. Heat the oven to 160°C/140°C fan/gas 3. Put the pistachios on a lipped baking tray and roast for 5 minutes until fragrant. Wipe out the food processor, add the pistachios and pulse until coarsely ground (or grind in a pestle and mortar). Transfer to a bowl. Add the butter and sugar to the food processor and whizz until smooth, then pulse in the egg yolk and vanilla extract, followed by the flour and ground pistachios, until the mixture just comes together. (Or cream the butter and sugar using a wooden spoon, then beat in the rest of the ingredients.) Set aside.
3. Roll out the pastry on a lightly floured work surface to a 15cm x 30cm rectangle, 2-3mm thick. Use a saucer to cut out 2 x 14cm pastry circles, then use to line the tart cases. If the pastry is a little crumbly, press any broken pieces into the tin to patch up gaps. Trim the tops using a sharp knife, then line with baking paper and fill with ceramic baking beans or uncooked rice and chill for 45 minutes.
4. Meanwhile, halve and core the apple, then use a sharp knife or mandoline to cut into thin (1.5mm) half-moons. Put in a saucepan with the rosewater, half the jam, the caster sugar and a drop of food colouring, if using. Pour over 200ml cold water, then bring to a simmer over a medium heat. Simmer gently for 2-3 minutes, then use a slotted spoon to transfer the apple slices
   to a plate. Keep the pan on the heat and continue simmering until the liquid is reduced to a thick syrup, then strain through a sieve into a jug/bowl and set aside.
5. Once the tart cases have chilled, bake for 25 minutes, then remove the baking beans/rice and bake for another 5 minutes until the bases feel sandy. Remove from the oven and cool.
6. Increase the oven temperature to 180°C/160°C fan/gas 4. Put ½ tbsp of the remaining jam in the middle of each pastry case, then spoon the frangipane mixture over the top.
7. To make the apple roses, lay an apple slice on the left-hand side of a large chopping board with the flat side facing you. Add a second slice next to the first, overlapping it halfway. Continue in a long line across the board until you’ve used half the apple slices or reached the edge of the board. Starting from the left hand side, carefully roll up the line of apple slices into a rose
   shape (the ‘rose’ will sit flat when completely rolled). Repeat with the remaining slices to make a second apple rose, then press any remaining slices onto the sides of the apple roses.
8. Gently press each apple rose into the frangipane in the tarts. Chill the tarts for 15 minutes, then transfer to a baking tray. Bake for 25-30 minutes until the frangipane is set and golden.
9. Remove the tarts from the oven and put on a cooling rack. Using a pastry brush, brush the apple roses with the reserved syrup as they’re cooling. Serve warm or at room temperature, with ice cream or clotted cream.