Sunchokes are one of the most under-utilized ingredients of the fall and winter. It could partly have to do with their strangely gnarled appearance. Or maybe it's their flavor, which is somewhere between potato and jicama, with the sweetness and crunchiness of the latter. It can be eaten raw, though unless you seriously enjoy gas, I wouldn't recommend indulging in too much (it's historically notorious for its odoriferous side-effects). Sliced, battered, and deep-fried tempura-style, it's excellent (but what isn't?). It's great sauteed or pureed as sweet, nutty accompaniment to meat.
But for my money, it's best as soup, and even better when it's been caramelized in a bit of brown butter before turning it into said soup.
The process is simple: brown some butter, then brown some sliced sunchokes in it. Add some leeks and onions to soften, flavor it all with a bit of sage and garlic, simmer, puree. The results are far more complex, with a deep, rich nuttiness from the sunchokes bolstered by the brown butter, and a distinct sweetness coming through at the end. I like to season it with a bit of vinegar to brighten it up (though lemon juice would work just fine as well). Sage and brown butter are a classic pairing, and it works perfectly well in this context too.
You can serve the soup as is, but for a more fall-inspired pairing, try stirring in some brussels sprouts sauteed with bacon at the end. The flavors really work well together.
Warning: Sunchokes are not for everyone. My wife can't stand the taste of them, and on average, I'd say about 15% of folks who try them are a bit turned off. But for the rest of us, few things scream fall more loudly.