Please know that no ingredient is necessary. You do not have to include oil, garlic, etc. This is what Frankie can tolerate, so it's what I do. Also, you can substitute fruit or anything for the fish, garlic and parsley. I made a variation of this recipe by boiling raisins and dried cranberries for the broth, then using them in the dough along with some cinnamon.  The didn't come out as pretty as the recipe below, but Frankie just adored them!

4 c. water
4 c. dry instant mashed potatoes (the generic store brands work best, as they do not have other ingredients)
3/4 lb. catfish (or fish of your choice)
2 T. parsley (dry or fresh)
1 t. garlic (minced)
2 t. Vegetable Oil (100% vegetable oil, can use safflower oil or any other oil that your dog can tolerate)

Pre-heat oven to 350 degrees.

Boil fish with the skin on in water for 10-12 minutes (until fish is flaky).
In the meantime, mix potato's, parsley, garlic, and vegetable oil. When the fish is done boiling, add 2 cups of fish broth to the potato mixture and knead until batter is stiff.

Wet the counter with a sponge and put a sheet of wax paper on the counter (you can also use a non-stick rolling pan and pastry board, instead of dealing with the wax paper). Take half of the dough and put it on the paper. Place another sheet of wax paper on top of the dough. Roll out with a rolling pin until dough is 1/4 inch thick. You will need to change the wax paper with every new batch of dough.

Cut the rolled out dough with a cookie cutter, place on an ungreased, non-stick baking sheet and put into the oven. Turn cookies after 15 minutes of baking.

Bake for another 10 minutes or until golden brown and slightly curled at the edges. You may let the cookies cool on the top rack of the oven for crispier cookies, or let them cool on a cooling rack outside of the oven. Either way, the cookies come out crunchy.

Keep cookies at room temperature. To extend the freshness of the cookies, keep them in the fridge. Freeze the cookies for even longer freshness. Makes approximately 40 cookies (more or less, depending on the size of the cookies).