Probably the same way treats for children are marketed, because they have the same requirements: it has to appeal to both children’s hedonism and parents’ desire to feel like they’re not feeding their children garbage.

Of course, that’s assuming humans can understand the higher beings’ marketing. If they can’t, it’ll be marketed just like pet treats: a claim that your humans will love it, plus a lot of reassurance that the treat is actually good for your pet humans.