Okay, anyone who has the (mis)fortune to be acquainted with me will know that I am not exactly Nigella in the kitchen...I once made chicken noodle soup which I rechristened into a dish called 'chicken sludge' as it seemed more appropriate (think one massive mass of noodles with the odd carrot or piece of chicken in!)...but even so, it was my lovely cousin Naomi's birthday yesterday so today, in her honour, I decided to attempt making cupcakes, and as you can see, they were a success! (Not a blackened, charred mass of inedible monstrosity). I googled "rainbow cupcakes" to find a recipe which didn't seem too frightening, and came up with this one at cutoutandkeep.net, which I will now proceed to share with you, if you don't wish to click the link :)
You will need:

125 g butter
125 g self-raising flour
125 g caster sugar
2 eggs
Vanilla extract
3 tbsp milk
Food colouring
Cupcake cases
1. Preheat oven to 200 degrees C.
Round up your ingredients.
Beat the sugar and butter together, until fluffy and light coloured.

2. Beat in the eggs one at a time, adding a little flour each time, until you've added it all.

3. Add the vanilla essence, mix.1 tbsp milk, mix.
1 tbsp milk, mix.
1 tbsp milk, mix.

4. Divide between 6 bowls:
Bowl 1- Add half a cap full of red colouring
Bowl 2- Add half a cap full of red and half a cap full of yellow
Bowl 3- Half a cap of yellow
Bowl 4- Half a cap full of greenBowl 5- Half a cap full of blue
Bowl 6- Half a cap full of blue, half a cap full of red.
Mix each colour throroughly (I found orange and indigo needed more mixing than the others)

5. Divide the purple bowl between the 12 cases and smooth to form bottom layer.
Repeat with the other bowls in this order:
Blue
Green
Yellow
Orange
RedPut in the oven for 15-20 mins (I did mine for 18 and they turned out fine!)

6. Decorate to your heart's content! My sister and I used buttercream and edible glitter and the results were interesting, to say the least!