Put all the curd ingredients in a saucepan over a low heat, stirring constantly, until the mixture thickens, about 5 mins. To check if it’s ready, dip a wooden spoon in and blow on it gently. If a wave-like pattern forms, remove from the heat and sieve into a bowl. It will thicken more as it cools. Tip into a sterilised jar and leave to cool completely.
Beat the butter and sugar together in a large bowl. Mix in the egg yolks and the vanilla extract, then add the flour, almonds and a pinch of salt. Work everything into a smooth dough with your hands, then wrap and put in the fridge for 1 hr.
Heat the oven to 170C/150C fan/ gas 3. Roll out the dough on a floured surface to a thickness of 4mm. Press out stars using the larger cutter, then make a hole in the middle of half of the biscuits with the smaller star cutter. Re-roll the excess, making sure you don’t overwork the pastry, and stamp out more biscuits. Put the biscuits on a baking sheet lined with baking parchment, and bake for 10 mins until golden. Leave to cool on the baking sheet.
Spread the lemon curd on the biscuits without a hole, and put a biscuit with a hole on top of each one. Dust the biscuits with icing sugar. Will keep in an airtight container for up to three days.Recipe adapted from Let it Snow by Agnes Prus (£7.99, Hardie Grant). Photographs © Frauke Antholz.