Preheat the oven to 180C Bake. Line and grease a 22cm cake tin.
Place zest, oil, eggs, and sugar into a bowl and, using an electric beater, beat for 3-4 minutes until thick and creamy. Note, if you don't have an electric beater you can use a food processor for this as well.
Add the salt, yoghurt and lime juice and beat again for another minute. Stir in the coconut. Note: if using long-thread shredded coconut, chop it roughly before adding to the cake so the strands aren't too long.
Sift in the flour and baking powder and gently stir with a wooden spoon until well combined. The mixture will be very runny.
Pour into the prepared cake tin. Bake for 45-60 minutes until a skewer inserted into the centre of the cake comes out cleanly. Allow to cool in the tin for 10 minutes before turning out onto a wire rack and cooling completely before icing.
To make the icing, combine the icing sugar, melted butter and lime juice in a bowl. Add enough hot water, 1 tsp at a time, to form a thin paste, about the same consistency as pouring custard. Spread or pour over the cake, sprinkle with the extra lime zest and coconut and allow to set.
Serve with a side of yoghurt or whipped cream and a nice cup of tea.
Recipe by The Fare Sage at https://www.thefaresage.com/lime-coconut-sponge-cake/