Well, the answer is really not that exciting. Simply put, there is more than one type of sweet potato. Some are the bright orange-fleshed ones we're used to, but others are pale yellow like the one above. So, are they interchangeable? We just ate ours for lunch, and...
...it tastes a lot like a sweet potato. Not so dramatic, eh? But we do have a few thoughts:
We read often that white sweet potatoes are less sweet and more starchy than their orange counterparts. They are frequently recommended as a substitute for regular potatoes, but we beg to differ. While white sweet potatoes are slightly less sweet than orange ones, they are no russets or yukon golds.
We ate ours roasted in the oven and topped with some butter, salt, and brown sugar (only one one side, though, so we could do a clean, objective taste test). A cooked white sweet potato is drier than an orange one but still creamy with a little butter mixed in.
If you like sweet potatoes but want a milder flavor, we'd use white sweet potatoes instead—they can go savory or sweet. One tip: We did find that our white sweet potato didn't stay firm and fresh as long as other potatoes, so eat fast!
And as for the difference between sweet potatoes and yams, that's another story. Read our explanation of that here.
Related: Sixteen Kinds of Potatoes
(Image: Elizabeth Passarella)