Whisk the butter, sugar and salt in a bowl. Add the eggs one at a time and continue to whisk until the mixture becomes lighter in colour. Stir in the buttermilk and food colouring. Mix the flour, coconut flakes and baking powder, fold into the mixture using a rubber spatula. Transfer the cake mixture to the prepared cake mould.
Approx. 50 mins. in the lower half of an oven preheated to 180°C. Remove from the oven, allow to cool a little, tip onto a cooling rack and cool completely.