A few years ago I was assigned to bring the "yams" to Thanksgiving. I started asking around how others prepared them. There is always the typical chop them up with butter over and marshmallows.. which is good. I thought I would do that until my girlfriend introduced me to this recipe and I just love love love it. It has a nice crunchy sweet crust and creamy base. I've considered having it as a dessert!
Trick question. Niether! They are both sweet potatoes! The US government was a little confused on the labeling and has labeled the orange variety as a "yam." When in fact it is not even related in a yam. Apparently true yams are huge and dark/blackish. ? Anyway.. my point is both are simply sweet potatoes just different colors and textures. And both very very yummy! You can choose your favorite for this casserole, I've done both and love both! This time around I used the yellow sweet potato.