Welcome to the Cake Decorators Q&A
Hi olgahunt
Is it a cake or a topper tutorial which you are looking for? At present there is neither tutorial available on the site.
However Paul does have a very good golden Labrador dog tutorial which could be used as a guide for the stacking and carving. If used in conjunction with the many images and some semi tutorials online, the dog could be quite easily be adapted into a unicorn! For both cake semi tutorials and for topper tutorials search in google images for’unicorn cake tutorial’. To see Paul’s dog tutorial take a peek here:
Rocking Rudolph tutorial could also be adapted if you wanted to have a standing structure. See Rudolph here:
Obviously with each you’d need to make changes as appropriate by following unicorn images.
Hope this can be a starting point.
