This is one of my SO's favorite Thanksgiving foods, and my SO insists that using the root vegetables sold in the US as yams is vastly preferable to using sweet potatoes (for a discussion of the differences between yams, the vegetables sold in the US as yams, and sweet potatoes, see this post).
This recipe is apparently an old family recipe of my SO's (i.e., it was made by my SO's family when my SO was a kid), and is this week's end-of-the-week recipe blogging post.
3 pounds yams (a variety of sweet potatoes)
5 tablespoons frozen 100% orange juice concentrate
2 tablespoons butter
3 tablespoons sour cream
0. Preheat the oven to 400F.
1. Wash the yams (leaving the skin on), and then cut off any blemishes or bad spots. Stab each yam multiple times with a knife to prevent explosions in the oven.
2. Place the yams on a baking sheet (lining the baking sheet with foil can make cleanup easier, as the yams often ooze a bit of syrup). Bake at 400F until a knife or fork easily pierces the yams. This will likely be about an hour, though it depends on the size and shape of the yams.
3. Remove the yams from the oven and let cool until they can be handled comfortably (at least 20 minutes).
4. Remove the skin (including the hardened layer that formed wherever you removed the skin in step 1). The skin sometimes peels off nicely by hand; otherwise cut off the skin with a small knife.
5. In a large bowl combine the peeled yams, orange juice concentrate, butter, and sour cream, and mash (with a fork or potato masher) until well-mixed and smooth.
6. Serve warm.
The amounts of ingredients in this recipe are flexible; vary to suit your tastes. This recipe is also very easy to scale up to feed a large number of people. My SO prefers using concentrated orange juice because it provides more flavor without watering down the yams; if all you have is regular orange juice, that should work fine.