Ingredients

Step by step

1. Preheat the oven to 180°C, fan 160°C, gas 4. Line 2 trays with baking paper.
2. Put the caster sugar, flour, cornflour, salt and butter into a large mixing bowl and rub with your hands until it resembles breadcrumbs. Add the egg and the citrus zests and bring together into a soft dough.
3. Roll out the dough on a floured surface, to about 5mm thickness. Use a round 6cm biscuit cutter to cut out as many circles as you can, then a smaller cutter or end of a piping nozzle to stamp out a hole in the centre of each biscuit. Transfer carefully to the trays and bake for 10-12 minutes until pale gold. Leave to cool for 10 minutes on the trays before transferring to a wire rack to finish cooling.
4. Put the juice of 1 orange and 1 lemon into a jug and mix. Put the icing sugar into a large bowl and add the citrus juice, a little at a time, until you have a smooth but thick icing. Divide between 3 small bowls and use your food colouring to dye one pale orange and one pale yellow, leaving the final bowl white.
5. Dip half your biscuits, flat side down, into the yellow icing, holding the biscuits upside down to let the excess icing drip off. Transfer carefully to a sheet of baking paper on the worktop, icing side up. Repeat with the other half, dipping them into the orange icing.
6. Using a teaspoon (or a piping bag with a fine nozzle), drizzle lines of the white icing across each biscuit. Leave to set.