Grease and line a 20 X 20cm square baking tin with baking paper (allowing the edges to overhang).
Sift the pure icing sugar and cream of tartar into a bowl.
Add the condensed milk and coconut and stir until well combined.
Divide the mixture equally into two bowls.
Add the pink food colouring, one drop at a time, into one of the bowls, until desired colour is achieved and stir well to combine.
Press the white mixture into the base of the prepared baking tin and use a spoon to firmly press down and level out.
Carefully spread the pink mixture over the top and press down firmly.
Refrigerate for at least 2 hours to allow to fully set before cutting.