Boston bun

Preheat oven to 200°C. Draw an 18cm round circle on baking paper. Turn paper over and use to line an oven tray. Put potato and sugar in a bowl and stir until well combined and sugar has dissolved. Sift flour and spices over potato mixture. Add sultanas and milk, then stir to form a stiff mixture. Turn out onto a lightly floured surface and gently knead until smooth. Do not over-mix.

Transfer to prepared tray, forming into a round dome shape within marked circle. Bake for 25 minutes or until cooked through when tested with a skewer. Transfer to a wire rack to cool.

Meanwhile, to make icing, put butter, icing sugar, milk and vanilla in a small bowl and beat, using an electric mixer, until well combined and smooth. Add pink food colouring, if using, 1 drop at a time until desired colour. Spread icing thickly onto cold bun, leaving a 3cm border around edge. Sprinkle with desiccated coconut. Slice and serve at room temperature. Spread with soft butter, if you like.