Preheat the oven to 160°C fan and line a 9" square tin with baking parchment
Beat the butter and sugar together until smooth
Add the flour, eggs and vanilla extract and beat together
Pour into the tin and spread
Bake for 35-40 minutes and then leave to cool fully
Add the icing sugar and vanilla extract to a bowl, and slowly add water until thick and smooth
Pour over the cake, and then sprinkle with Christmas sprinkles
Leave to set and enjoy
