My little girl is as baking crazy as I am. We bake cakes together every week, I try to introduce a little variety but week in week out her favourite recipe is vanilla cupcakes. For a girl who used to turn her nose up at frosting she certainly makes up for that now! We don't get much variation in the colour scheme either but I suppose I should embrace her love of all things pink and pretty before she grows out of this lovely phase.
When baking with the kids, I try to let them do all aspects of the cooking. This normally means ditching the stand mixer or processor and going back to a large bowl and wooden spoon. They (my little boy joins in too) sit up on the work top along side a bowl that is nearly as big as them and armed with their favourite wooden spoons they get stuck in.
For these cakes we made a victoria sponge mix covered in a cream cheese frosting. The piping of the icing is the trickiest bit for a four year old so we both do it together. The decoration is left completely up to the kids. My daughter is surprisingly neat and very artistic. I think she's going to make a fantastic baker, my son on the other hand is definitely going to be more of a taster!