Put the butter, sugar and vanilla in a mixing bowl and beat, using an electric whisk, for 6-8 mins, until pale and creamy. Add the flour, coconut, egg and a pinch of salt. Mix for a further 2 mins, or until a dough forms.

Roll out the dough between 2 sheets of nonstick baking paper to 5mm thick; chill for 30 mins.

Preheat the oven to gas 4, 180°C, fan 160°C. Using a 5cm cookie cutter, stamp out about 20 rounds, re-rolling as required. Using a 2cm cookie cutter, stamp out the middle of each round to make a ring and discard (or re-roll to make more biscuits, if you like).

Arrange the rings on a nonstick baking sheet and bake for 10-12 mins, or until lightly golden. Leave to cool on the baking sheet for a few minutes, before transferring to a wire rack to cool completely.

To make the icing, sift the icing sugar into a large bowl and add enough freshly boiled water to produce a thick, spreadable consistency. Divide the icing into separate smaller bowls, adding a different food colouring to each.

Using a teaspoon, spread each ring with a single colour icing, then drizzle over lines in a contrasting colour. To create a feathered effect, drag a cocktail stick through the icing in 1cm intervals. Repeat with the remaining biscuits in different colour pairings. Leave to set on a wire rack before serving.