Yet this fear is misplaced. Making a novelty cake, and revealing it to the child (as the best cakes are surely always a surprise), should be easy, as long as you follow six simple rules.
1. Less is more.
A novelty cake should get across the essence of what you are portraying, not be an accurate representation.
One of the best cakes my mum ever made, at short notice and for a school fete when I forgot to tell her in advance that we were meant to take in a cake, was a fish bowl. She made a round cake, covered it in blue icing and dotted chocolate fish from the newsagents down the road on it. There were no castles for the fish to swim in and out of, no plants and no starfish, but you knew instantly what it was meant to be when you looked at it.
2. Not everything has to be edible.
The decorations are there to be ooohed at, but the cake is what we really want to eat, so don't fret about using non edible decorations.
Green icing covered in Subbuteo players becomes a football pitch, Yellow icing with brown sugar and a toy palm tree becomes a beach, red icing with a toy spaceship on it becomes Mars.
3. 2D is as good as 3D.
You want to make a giraffe cake? There's no need to have one that stands up with a neck that doesn't collapse. Make it 2D and you can cut shapes out and lie them flat.
4. Inspiration is everywhere.
Other easy ideas include flags (coloured icing or sugar paste in strips or blocks to replicate to the pattern of the flag, a garden (buy ready made sugar flowers and place them anywhere on the cake) and sports (another classic from my mum was a green cake with coloured gobstoppers to make a snooker table).
5. Ready made is fine.
You could pipe your own letters (in which case I recommend Lakeland's silicone piping set, £9.49), or you could buy ready made letters such as Silver Spoon's Chocolate Letters and Numbers (£.1.29 in Sainsbury's).
6. Choose your icing carefully.
There are four main types of icing you can choose from:
Glacé icing is made by mixing icing sugar, water and whatever food colouring you want (or none for white icing). It's gloopy and can run but remains my favourite as it tastes so good.
Butter icing is made by creaming (mixing together with the back of a spoon) butter and icing sugar and is great for thick coatings of icing or creating textured surfaces such as a sea or a snow covered mountain.
Royal icing is made from egg white, lemon juice and icing sugar. It's the kind of icing used on Christmas cake and traditional wedding cakes. Because it sets hard, and because it's hard to cut neatly, it's not great for children's cakes.
Sugar paste is a pliable icing made from icing, water, gelatine, glycerine and liquid glucose – I advise buying it ready made. It's great for modelling as it can be used like plasticine.
The consistency of all of these is up to you – play around with the liquid/icing sugar ratio and see what gives the effect you want.
A palette knife dipped in hot water is your key tool – it will help it spread smooth and erase any mistakes.
Do you make and decorate birthday cakes or opt for shop bought?
What have been your biggest successes (and disappointments!)?