You must have soft butter for this or it won't work. If butter isn't soft check out my post on how to soften butter quickly for baking! Preheat your oven to 170c fan.

Put all ingredients in the bowl and mix on low speed initially until just combined then for approx 1 minute on a higher speed until it looks like cake mixture. It's ok if there's a few lumps though if your butter is soft this shouldn't happen. Don't mix it for too long, as it'll make the cake tough, it's ready as soon as it looks like cake mixture!

Grease and line your tin. I am icing mine in the tin, so I keep two edges of the baking paper overhanging the side to make it easy to lift out. Pour cake into tin, level out and put into the oven. Set timer for 20 mins.

Check if it's cooked after 20 minutes, it could take 25. Press down gently on top in middle, if it springs back it's cooked. You can double check by inserting a small skewer or knife into centre, it should come out clean.

Allow to cool before icing. Sieve icing sugar (I always always regret it if I skip this step, you will have lumpy icing), add 4 tbsp hot water initially and stir well. You may need more, I think I had about 6. You can always add but not take away so start low and add more if required. Add colouring and pour over cooled cake before sprinkling your sprinkles!

Allow to set and enjoy with a cup of tea