R' Daniel Israel wrote to Areivim:
> My experience is that Parmesan is almost invariably eaten either
> melted, or very finely ground, or both, and my understanding is
> that this would obviate the halachic requirement for waiting.

R' Micha Berger asked:
> Could you provide a mar'eh maqom?

ArtScroll's "The Laws of Kashrus" by Rabbi Binyomin Forst, page 209, 
says, "One who eats 'hard' cheese that has been melted into food 
(e.g., lasagna) need not wait six hours."

His footnote says, "Yad Yehuda 89:30k. It would seem that this 
applies only to cheese melted *into* food, but if the cheese is 
melted *onto* food (i.e., it is still visible as a separate entity), 
it retains its status. Thus, one who eats Swiss cheese melted onto 
toast or a cheese omelette made with hard cheese is required to wait 
six hours before eating meat."

The question of whether RDI's case (where parmesan cheese is finely 
ground and mixed into a salad) is more similar to lasagna or more 
similar to an omelette, is left as an exercise for the reader.

Akiva Miller