First Thanksgiving dinner with future in laws.?

My boyfriend of 5 years wants me to go to thanksgiving dinner with his family. Naturally I'm petrified and extremely nervous. His family hasn't really approved of us dating in the past, because of our family religious differences (they are extremely LDS). There will be people there I have never met before and I don't really know his immediate family very well. His mom is an amazing cook and even teaches cooking cles to the neighbors a couple times a month. I want to make something to impress them but I don't know what to bring. I was thinking a dessert of somekind since that is what i'm best at. Any suggestions? I do know how to make amazing cinnamon rolls and candied caramels but I don't know if those are really thanksgiving dinnery...i could make them for christmas. Problem too his mom hates chocolate so I want to avoid that.