Preheat the oven to 180ºC/350ºF/gas 4. Grease and line 3 x 20cm sandwich tins.
Using an electric whisk, cream 300g of unsalted butter and 300g of golden caster sugar together in a large bowl for 2 to 3 minutes until pale, light and fluffy.
One at a time, crack in 4 large eggs, whisking each in before adding the next. Sieve in 350g of self-raising flour and carefully fold through along with 100g of desiccated coconut. Pour in 200ml of light coconut milk and fold until well combined.
Divide the mixture equally between the prepared tins and lightly tap each one to make sure the mixture is even and smooth.
Bake in the hot oven for 20 to 25 minutes, or until golden and a skewer inserted comes out clean. Leave to cool for 5 minutes in the tin, then tip out onto a cooling rack to cool completely.
While the cake is cooling, get on with making the jam. Peel, destone and roughly chop 1 large ripe mango (240g), then place in a medium pan along with 50g of golden caster sugar and a splash of water.
Bring to the boil over a medium heat and continue to boil for 10 minutes, or until the mango has started to break down and is thick and jam-like. Add a splash of water to loosen if needed, then carefully mash with a potato masher and set aside to cool.
To make the lime icing, use an electric whisk to beat 200g of unsalted butter in a large bowl for 1 to 2 minutes, or until soft and creamy.
Beat 100g of cream cheese in a small bowl, then add to the butter and gently mix until combined. Add 1 teaspoon of vanilla extract and gradually sift in 500g of icing sugar, beating as you go. Continue to beat for a further 1 to 2 minutes, or until white and fluffy.
Finely grate the zest of 1 lime and set aside, then squeeze the juice into the icing and beat to combine.
To assemble the cake, dab a little of the icing onto a cake stand (this will hold the cake in place), and place one sponge on top.
Cover with a layer of icing about 1cm thick, then top with half the mango jam. Repeat with the second sponge, then top with the third sponge, leaving the top of the cake plain.
Using a palette knife, spread the remaining icing over the top and sides of your cake, until completely covered.
Sprinkle over the lime zest and pop some cute Easter decorations on top, if you like.