This rainbow cake got a spectacular reception and it is so easy to make. There are two key elements to making this cake spectacular.
The first is using pastes or gels for a deep, rich colour. Supermarket bought colours tend to be watery and lack the vividness of pastes and gels. These are easy to purchase on-line or at cake decorating suppliers. I used “Creative” colour pastes and an “AmeriColor” gel (yellow). These are the brands I had on hand at the time.
Get ready to bake before you start. Make sure:
You can make the butter cream icing while the cakes are cooling.
The second thing in making this cake tremendous is ensuring your layers are uniform in size. Ideally you’d have six identical cake tins and six identical bowls so you could compare quantities easily.
I had to make-do with three bowls, only two were similar in size. I was careful to get the levels as close to even as I could BEFORE adding colour.
Remember: once you add the colour, you can’t take it out.
I poured my coloured cake mixture into the prepared tins and checked the levels again. At this point the only way to even them up is to scoop a little out of any larger layers.
Bake your cakes.
Remember: the cooking time will be significantly reduced as the layers will be much thinner. Make sure you keep a close on them whilst cooking.
Once you’ve baked all your layers and they have cooled, get ready to stack them. If you haven’t made your butter cream icing yet, do so now
Place your starting layer colour on the plate. You may want to start with red or purple. I started with red, then orange, yellow, green, blue and finished with purple.
Between each layer spread a little butter cream icing.
Continue to place each layer on top of next with butter cream in the middle until you have all layers in place.
Spread a thick layer of butter cream over the whole cake. Don’t worry if it’s a bit rough. Be generous with the icing as it makes it easier to smooth out later.
Once the icing covers the cake, put it in the fridge to set.
Tip: I use a “lazy Susan” or turn-table to help get an even edge on my cakes. You don’t have to but it does make it easier.
Place the roughly iced, chilled cake on the turn-table.
First, smooth the top of the cake.
Next, using a long, smooth metal knife (pre-heated with boiling water) run it around the edge to smooth the sides.
Keep finessing until you’re happy. If you need add more icing, re-chill the cake and re-heat the knife, and repeat the process.