1Grease a 6cm-deep, 20cm square cake pan and line the base and sides with baking paper, extending it 2cm above the edges.
2Sift the icing sugar and cream of tartar together into a large bowl. Add the condensed milk, desiccated coconut, and vanilla essence. Mix until well combined.
3Divide the mixture into two equal portions. Tint one portion pink with the food colouring, leaving the other portion plain.
4Press the plain mixture over the base of the prepared pan, levelling the top with the back of a spoon. Press the pink mixture over the plain layer, levelling the top with a spoon. Cover and chill for 3 hours or until set.
5Cut the coconut ice into 2.5cm squares and serve.