Hi there! I remember (and still crave) Cosmos!
I was missing Westchester and did a search for "Cosmos Pizza" just in case I might find it and found your post. I was a student at Manhattanville down the road in Purchase back in the '80s and Cosmos was THE place to go for pizza. I can even remember walking between the two dining rooms to get to the rest room
. But the pizza! It was definitely different than the usual "pizza parlor" slice...the only thing I could ever compare it to was the pizza from the Greek restaurants in Boston. My college roomate (a Bostonian) told me that it was a lot of olive oil in and then under the crust that made it so good. I don't know if that helps!
I met my husband in the late 80s and took him to Rye so he could experience the Pizza and sadly, it was gone. We live in the deep South now and there are a couple of transplants (one from Briarcliff Manor!) who make decent pizza, but Cosmos was in a class by itself. Thanks for bringing back a really good memory! Cheers, happy new year!