I make liver brownies similar to blisscodisco's, using wheat flour instead of oatmeal......but I'll try the oatmeal!
Chili LOVES them. I find that the bake time is very sensitive - baked too long, they crumble apart, baked too little, they are too sticky....but when I get them baked just right they are wonderful even after freezing.
For grain free, you could try tapioca flour.....I might try that myself just for fun. Tapioca flour is cassava root, very easy on the digestive system, and not a grain. Might be worth a try. I'm thinking they may need to bake longer using tapioca flour....not sure. I'll give it a try and report back in!
I also make chicken jerky using chicken thighs. Very easy to slice thin if you freeze them first and then let them sit out and defrost just enough to be sliceable. I lay the slices out on a cookie sheet and back at 200-250 until they are thoroughly crispied.
These make good cat treats, too. Chili and Bamboo both are like vultures when I'm making liver brownies and Chili's Christmas Crunchies. Ever see a cat do competition heeling? LOL