A citrussy blueberry compote makes the perfect night-sky backdrop to the moon and stars in this deliciously sweet vegan tart.
Heat the oven to 200°C/180°C fan/400°F/Gas 6.
Make the pastry. Put the flour, sugar and salt in a food processor and pulse to combine. Add the coconut oil and pulse again until the mixture resembles breadcrumbs. Add the cold water and pulse again to form a dough.
Tip out the dough onto a lightly floured work surface and gently knead together. Wrap the dough in cling film and chill in the fridge for 30 minutes.
Meanwhile, make the filling. Place the blueberries, sugar, lemon juice and zest, cornflour and vanilla seeds in a pan over a medium heat (you can submerge the vanilla pod in a jar of sugar to make vanilla sugar, if you like).
Cook, stirring, until the berries are tender, then bring to the boil and cook for 2–3 minutes, stirring, until thickened. Transfer to a bowl and leave to cool.
Roll out the chilled pastry on a sheet of baking paper to a 25cm circle, about 5mm thick. Using a rolling pin, carefully lift the pastry circle and use it to line the sandwich tin, pressing it into the corners of the tin with your fingertips. Trim the excess and reserve the trimmings to use for decoration. Prick the pastry base all over with a fork. Chill for 15 minutes.
Roll out the pastry trimmings on a sheet of baking paper to a disc 5mm thick. Use the edge of a saucer to cut out a neat crescent shape and use the mini star cutters to cut star shapes from the remainder of the pastry disc. Discard the trimmings.
Slide the baking paper (with shapes) onto a baking sheet and place in the fridge to chill for 15 minutes.
Line the pastry case with scrunched-up baking paper and pour in the baking beans. Bake blind for 10 minutes, then remove the baking paper and beans. Sprinkle the desiccated coconut onto the base of the pastry case and return it to the oven for 7 minutes, until golden.
Spoon the cooled blueberry mixture on top of the coconut layer and return to the oven for a further 5 minutes. Leave to cool in the tin while you bake the decorations.
Remove the pastry decorations from the fridge and bake them for 5–10 minutes, until lightly golden.
Release the cooled pie from the outer ring of the sponge tin and slide it off the base of the tin onto a serving plate. Decorate with the moon and star shapes to finish.