Lemon and poppy seed Easter biscuits

Method

1. Whizz the sugar and almonds in a food processor to a fine, sandy texture. Add the flour, butter and lemon zest, then whizz again until the mixture forms fine crumbs. With the motor running, add the egg, egg yolk and poppy seeds, then pulse until the dough comes together. Divide the dough into 2 equal pieces, then roll each between 2 sheets of baking paper to 2-3mm thick (about as thick as a £1 coin). Stack the sheets of dough (still in between the baking paper) on a baking sheet and chill for at least 1 hour until very firm.
2. When ready to bake, heat the oven to 160°C fan/gas 4. Remove the dough sheets from the fridge and carefully peel away one piece of baking paper. Cut out desired shapes, carefully removing the excess dough (roll again to make more), then use a smaller cutter to make a little ‘window’ in half the biscuits.
3. Slide the biscuits, still on baking paper, onto 2 large baking sheets and bake for 8-10 minutes until firm and very pale golden. Transfer the biscuits to a wire rack and cool completely (see Make Ahead).
4. Spread lemon curd over the biscuits without cut-outs. Dust the top of the other biscuits (with the windows) with icing sugar (optional), then sandwich the biscuits together.