From Cosi's owner, Perry, who's given these out to the local pooches for special occasions (and had many requests for the recipe due to their popularity with the canine set):

LIVER BROWNIES
(for your doggie)

1 lb. liver, pureed in blender
1 small box Jiffy corn muffin mix
1/2-3/4 cup flour
1 rounded tsp. garlic powder
1 rounded T. parmesan cheese
1 T. oil
Mix ingredients. Spray large cookie sheet with PAM. Spread mixture on sheet. Bake at 350 degrees for 25-30 minutes. Cut into squares while hot, then cool. DOGS LOVE IT!
For Salmon Brownies, instead of liver, substitute one 16-oz. can of salmon (with juice) processed in food processor or blender. You may also need to add about half a cup of water.