Gluten Free, Casein Free Ultimate Chocolate Brownies

I copied this recipe from my mom's stash of recipes before getting married (lo, those many years ago). I think she got it from the back of a Hershey's cocoa tin. Here it is, adapted to be free of gluten and casein. It is decadent, chocolate-y, and oh, so yummy. The original recipe calls for frosting the brownies (see Creamy Chocolate Frosting), but they are already so rich that I omit the