Then there's royal icing - not nearly as expensive as it sounds. It's simply made by taking egg white (not trace of egg yolk at all) and adding icing sugar to it again until you've reached the desired consistency. It can be runny to spread over the cupcake, soft peak to hold it's shape, and firm peak, for piping decorations and writing.
My favourite icing at the moment, however, is Italian meringue. It sounds fancy, and it does take a little more time than other varieties, but it's light and fluffy and feels as though you're biting through a cloud, as I tried to illustrate above by adding a little soft focus to the picture displayed here - I made some of these cupcakes earlier today. I even coloured the icing blue instead of my trademark pink, to add to the dreamy feel! You need not be an expert baker or sugarcrafter to make this. If you can read and follow a recipe, you can make Italian meringue.
This recipe is an adaptation from the original taken from The Way to Cook by Julia Child. My version includes a smattering of rose water and a teaspoon of rose essence (optional). You could even substitute the rosewater for lavender water, or orange blossom water.
Enough to ice 24 cupcakes.
4 egg whites
1/4 tsp cream of tartar
1 cup sugar
1/2 cup water
In a saucepan, boil the sugar and water together. Boil on a low heat for 10-15 minutes. Keep a wet pastry brush handy to brush around the sides of the saucepan while the sugar and water boils, to prevent crystallising.
Keep boiling it until it reduces and goes 'syrupy' (I usually judge by dipping a teaspoon into the mixture, then tapping the teaspoon on a plate lightly. If it doesn't feel sticky at all, boil it a bit longer.
For those who want to do it 'by the book', the syrup should be about 112-116 degrees C on a sugar thermometer (soft ball stage). Just don't judge it by sticking your fingers in. You'll burn like mad and scream for mercy.
While your syrup is happily bubbling away, whisk your egg whites and cream of tartar together either with a hand mixer or a stand alone mixer. Keep it whisking away until you get soft peaks.
Once your syrup is definitely syrupy, you have to pour it in (while it's still hot) to the egg white mixture. This is the only really fiddly bit. Carry on whisking the egg whites at a moderately slow speed, and pour the hot syrup in, trying to pour it from a little height, so that it pours into a long, thin stream. (Try and picture the traditional way of pouring mint tea, like Arabs do. That's what you want.) Try to avoid pouring the syrup onto the wires of the whip.
Once all the syrup has been poured, keep beating the mixture and increase the speed until it's completely cooled down.
Once the meringue can hold its shape, it's ready to use. You can also add food colouring as you wish. I prefer to use powdered or paste colouring as this doesn't affect the consistency of the icing as liquids do. There's a great range at Squire's Kitchen, Sugarshack and Almond Art, and for South Africans, The Baking Tin and any baking retailer have a great range of Barco food colours.
Enjoy biting into a marshmallow-like dream.