Take whatever you need out of the fridge so that all the ingredients can come to room temperature. Preheat the oven to gas mark 4/180°C/160°C Fan/350ºF, and butter and line two loosebottomed, 20cm / 8 inch sandwich tins.Process the drained pineapple (reserving the juice just in case) and cream cheese until smooth and amalgamated. Add all the other ingredients, and process again to make a smooth batter. Spoon the batter evenly into the two sandwich tins, and cook for 20-25 minutes.Once they're done, they should be beginning to come away at the edges of the tin and spring back when gently pressed. Let them sit for 5 minutes in their tins on a wire rack, and then turn them out to cool. They will look disappointingly flat, but don't panic in the slightest: they will redeem themselves once they are iced. Once they're cold, you can get on with the gleaming white coconut icing.Arrange a bowl that fits over a saucepan of barely simmering water to use as a double boiler, and put the whites, sugar, syrup, salt and cream of tartar into the bowl. Whisk with an electric whisk over the simmering saucepan until the icing goes thick, white and glossy and is stiff enough to form peaks. This will take about 5 or so minutes. I have never attempted this by hand, but obviously it would be possible with a balloon whisk, but it might also be agonising.Take the bowl off the saucepan away from the heat and whisk in the coconut essence.Sandwich the cakes with just over a third of the icing, and then ice the top and sides in a swirly, snowy fashion. Immediately throw over the desiccated coconut to coat the sides and top of the cake.I don't bother with the paper square, though you could: I just brush off any stray bits of desiccated coconut from the edges of the plate, or just leave them where they've fallen.This cake looks wonderful in its uncut fluffy bouffant whiteness, but I like it best once you've sliced in, so that the chocolate layers gleam out darkly, striped and edged in brilliant white.