This is very close to the one in the book, the one in the book says you can substitute liverwurst, which I think is a bad idea. Be careful which soup you choose, while garlic isn't the huge no-no that some people suggest, onions are. The recipe comes from this site:
Dog Treats. Here's also a copy of that page of the book, but I not sure if it's ok to reproduce it.
Oatmeal liver cookies
1 lb. liver
2 eggs
3 Cups oatmeal
1 envelope dry Lipton soup mix
( the author used garlic & herb & veg, but have used others in the past with no ill effects)
1 1/2 teaspoons crushed garlic (in a jar in the produce section)
Puree liver in food processor. Add 2 eggs, dry soup mix and crushed garlic. Blend again. Pour into LARGE mixing bowl and add oatmeal. Mix well. Dump into well greased (Pam works great) cookie sheet or baking dish (lasagna pan works great). Bake @ 250F for 1 hour. Sprinkle top w/garlic salt, cut immediately and put into zipper baggies. Freeze extra.
Here's the one from the book.