This steak - actually the sauce for it - is possibly named after Diane, the Roman goddess of hunting. I can't see the connection myself, but there ya go. There are other theories for where the name comes from, and also competing ideas of the origin of the dish - London, New York, Belgium and Australia can all lay claim to it. Whatever - it's really tasty and stupendously easy to make.
Butter and oil for sautéeing.