I know a group of dogs of the same litter. A couple of weeks ago it was their birthdays, and I thought about exactly this. The kids thought about disgusting dog-food "cakes"...
These little-biccies went down well with all dogs offered (but then so did the stinky cakes...)
Step 1: Ingredients
These are simple, you don't need much:
Liver (I bought 99p worth of ox-liver)
Oil (I used redundant olive-oil from a jar of anchovies)