Heat the oven to 200C/180C fan/gas 6. Line two or three baking trays with baking parchment. Put the butter and sugar in a bowl and beat using a wooden spoon until smooth and creamy. Add the cardamom and egg and mix well. Next, add the flour and bring it all together into a soft dough. Cover and leave to rest in the fridge for 30-40 mins.

Roll the dough into a thin sheet, roughly 3mm, then cut out eight circles using a 10cm round biscuit cutter. Arrange on the prepared baking sheets and bake for 10-14 mins, until very lightly golden. Leave to cool completely.

Meanwhile, make the icing. Whisk the egg whites until they form soft peaks. Sift in the icing sugar and add the lemon juice, then beat until smooth. Divide into four portions and add a different food colouring to each of three, leaving one white. Put into separate piping bags and cut a tiny hole at the ends. Pipe colourful rangoli designs on the biscuits and leave to set. Will keep in an airtight container for up to three days.