First up preheat your oven to 180℃/160℃ fan/Gas mark 4. Grease and line a 30cm x 20cm baking tin.

Pop your margarine and sugar into a large bowl and cream together until light and fluffy. Add the eggs and Vanilla Extract and mix together until smooth and combined. Sieve the flour and Baking Powder on top and then fold in until just combined.

Pour your mixture into your prepared tray and smooth out to an even layer. Bake for 25-30 minutes until golden brown and a skewer inserted into the centre comes out clean. Leave to cool in the tin for 15 minutes and then transfer to a wire rack to cool completely.

Once your sponge it cooled, it is time to decorate; sieve your icing sugar into a large bowl and add the water in a couple of intervals mixing between each until you have a lovely smooth icing that has a thick pourable consistency (you may not need to add all the water).

Pour your icing over your sponge and smooth out to cover the top using the back of a spoon. 

Mix your Candy Mix Sprinkles together in a bowl and then sprinkle over the top of your cake. Ta-dah your are now ready to slice up your creation and tuck in!