R is for rainbow cake! A successful attempt at a birthday cake for a 6-year-old thanks to Kerry Cooks.

Gel colours definitely make your life easier. They are a little more expensive than liquid food colouring but they will last a long time. Just squeeze the amount you need onto a teaspoon and mix into your batter - no colour anywhere else.

This is no. 18 of 26 alphabetical bakes!

For the cake:
350 soft butter
350g sugar (I used caster)
6 eggs
350g flour (I used spelt, Kerry specifies self-raising)
3 tsp baking powder
1 tbsp vanilla extract
up to 40ml milk (I used rice milk)
gel food colouring
lollies, chocolates, marshmallows of choice

For the icing:
100g soft butter
250g cream cheese at room temperature
600g icing sugar, sifted
1 tbsp vanilla extract
1 tbsp lemon juice

You need 6 cake tins of the same size. I used 3 x 22cm sponge tins and baked them in 2 lots. You could also try and find disposable foil pie/flan tins from the supermarket. Line the tins with baking paper and grease the sides.

Preheat oven to 170C. Using a stand mixer or handheld mixer cream butter and sugar in a large bowl until light and fluffy. Add in eggs one at a time. Then slowly add flour, baking powder and vanilla.

If your batter is a little thick, add a little bit of milk to loosen. Divide batter evenly into 6 bowls. Best to use electronic scales to weigh it out.

Colour each bowl with 1/4-1/2 tsp of each gel colour to make red, orange, yellow, green, blue and purple.

Bake in batches in oven for 10-15 min until cooked through. Remove from oven and cool in the tins. Once completely cooled you can wrap each cake separately in cling film and freeze if you're going to prepare the cake another day. I cut out a 10cm circle in the centre of 5 of the cakes except the red one.

To make the icing soften the butter in a microwave for 10 seconds. Mix in cream cheese then the icing sugar to form a smooth icing. Finally add in vanilla and lemon juice. Chill in fridge.

When you're ready to frost bring the icing to room temperature and a soft consistency for spreading. Dab a few spots of the icing on your cake plate or stand and place the purple cake on top. Spread a thin layer of icing on the cake and stack the blue cake on top. Repeat with the green cake, then the yellow and orange. Chill in fridge for 10-30 minutes.

Remove from fridge and fill the hole with your chosen sweets. Spread a layer of icing on top of the orange cake and top with the red cake. Apply a crumb coating of icing over the whole cake and refrigerate until firm. Apply a second crumb coating if you wish (and chill again) or finish up with a final smooth layer of icing. Return to the fridge to chill.

I kept the decoration simple with just a band of sprinkles around the edge of the cake.

Our 6-year-old and her friends loved the surprise when I cut the cake and all the lollies spilled out.