This uses left-over chopped turkey. We grew up calling these turkey burgers - but that was before ground turkey, so I'm calling them turkey sandwiches to avoid any confusion. WE LOVE THESE. They were a favorite with my family when I was growing up, and now they are a favorite with my hubby and kids. Something nice and different. The melted cheese and mayo together are just heavenly. I like my cheese cut up in fairly large cubes, not diced. Adjust the onion to your taste. We look forward to thanksgiving left-overs just for this! FOR OAMC: leave out the mayo and freeze remaining ingredients (expect buttered buns) in an airtight bag with all of the air removed. Let thaw in fridge before adding mayo.