If you don’t have any flaked coconut, simply scatter the finished cake with 3 tbsp toasted desiccated coconut.
Any left over coconut milk can be stored in an airtight container in the fridge for up to a week or alternatively, pour into a freezer bag and freeze for up to one month. The thawed milk will be slightly grainy which is fine for baking but if you need it to be smooth for a sauce or curry, simply blend with a hand blender to re-emulsify the liquid.