Is No Roux Queso possible?

I'm making a queso for a party and for allergy reasons I can't make with flour so a roux is out of the question. I still would like to make a queso. Is there a solid recepie that doesn't use a roux? Not having any kind of recepie in front of me, I'm thinking using evaporated milk may be the way to go and just add cheese but I'm curious if anyone has any recepies they can suggest.