Preheat your oven to 170c. Take a 12 portion muffin tin and place a muffin case in each hole.
In a large bowl, mix the plain and coconut flour, baking powder, bicarbonate of soda, sugar, salt and desiccated coconut. This is your dry mix. Then in another bowl, mix the eggs, vegetable oil, coconut milk and vanilla extract. Then add in the lime juice. Pour this wet mix into the dry mix, give everything a stir until combined (don't worry, it's supposed to be a bit lumpy) and divide the mix between the muffin cakes. Don't overfill, make sure there's still a few mm of space to allow the cakes to rise. You may not need all the mix.
Place in the oven and cook for 20-25 mins until golden brown. Once cooked, take out of the oven and leave to cool in the tray for a few minutes. Then place on a cooling rack to cool completely.
Now make your topping. Place the sugar and cream of tartar in a small bowl with 2 tbsp. boiling water. Mix to dissolve the sugar. In a large bowl, add the egg white and start whisking using an electric whisk. Whilst whisking, slowly pour in the sugar mixture. Continue to whisk until the mixture forms stiff peaks. It will take 4 or 5 minutes. Finally whisk in the vanilla extract.
Spread the mixture over the cooled cupcakes, then sprinkle on the desiccated coconut. Finally garnish with the lime zest.
Tip You can store the unfrosted cakes in an air tight container and refrigerate. It should keep like this for 3-4 days..Nutritional Information is per serving.