To make the cake:
The cake mix is a very simple fairy cake recipe. 4oz caster sugar and 4oz butter creamed together then 2 large eggs mixed in until the mixture looks creamy. After that I add 4oz of Doves gluten free self raising flour and mix it all with an electric mixer until smooth. It will seem a bit stiffer than a normal cake mix but then add a teaspoon of vanilla essence and then mix in a tablespoon of milk and mix until it all looks fluffy, sometimes you might need to add a tiny bit more milk, I don't know why but it always seems to take a slightly different amount of liquid to work (I also suspect my measuring is not quite so accurate as it should be!). Fill muffin cases or cupcake cases and put in the oven for 15-20 minutes at 190C. Again, everytime I make them they seem to take a slightly different amount of time to cook, gluten free flour seems to work very differently depending on the weather, just keep an eye on them when they are in the oven but they are very forgiving if you leave them in too long.
Preparing the icing:
While they are cooking, clean up, then make up some buttercream. You need 75g butter that has been kept at room temperature, then sift in 175g of icing sugar but add it in bit by bit or it makes a huge cloud of icing sugar when you try to mix it! Once all the butter and sugar is mixed up add half a teaspoon of vanilla essence and a tablespoon of milk then beat it well. Taste the mix and if it is light, fluffy and soft it is done if not keep adding milk a drop at a time until it tastes right.
While the cakes are cooling I use readymade icing and pull a bit from the packet and mix a bit of black gel food colouring with it in a bowl until it is all a shark fin shade of grey. Then sprinkle plenty of icing sugar onto your worktop then roll out the grey icing and cut into shark fin shapes with a sharp knife. Don't worry that the shapes are thick with white icing sugar, it disappears. I put the fins out onto a plate then put them in the fridge to make them go hard a bit faster and it gives the shapes a sort of wet look. At this point we normally wander off to have dinner and then come back to them an hour or so later when they will have set.
I give my son the buttercream mix and then dip a fork in some blue gel food colour, he mixes the fork round in there which seems to give it perfect streaks that look like water. Then using a knife spread the coloured buttercream on the top of the cakes, using the fork to fluff things up a bit if needed. Then just push one of the shark fins upright into the top of each one of the cakes. I also have a silver lustre spray and give everything a quick spray with that to make the waves glisten.
That's it! Eat and enjoy, they went down very well with the kids at my son's school :) When doing them on my own these cakes take about 15 minutes to make and decorate, when working with children they take a little short of an hour but seem to disappear a whole lot faster!