Place it on a quarter sheet or small jelly roll pan to catch drip. Pop it into an oven at 375F . Remove it 45-60 minutes later when soft all the way through. Peel off the skin Add butter. That's it. Roasting is the only way to bring out the full flavor of the sweet potato. You can make it with glazes and so on, but if it's a holiday meal, there's already cake and pie and lots of rich food, so a well baked sweet potato can be more appreciated among adults than the sticky glazed version.
There is one other sweet potato dish you need to know. Something to use up all those deliciously roasted sweet potatoes left over from your holiday meal: Sweet pototo croquettes. (1) (2) (3)
Now, about that yam question. Botanically speaking, a yam is a very large, starchy root vegetable native to Indonesia. It's not orange in color like the sweet potato. And real yams are rarely offered for sale in the US. The Louisiana Sweet Potato Marketing Association registered yam as a trademark for sweet potatoes grown in their state. So most 'yams' sold in American supermarkets are sweet potatoes grown in that state.