To state it in the language of the SAT, sweet potatoes are to regular potatoes as that cool European exchange student is to the popular kids in your high school. No matter how great regular fries seemed before, one bite of the exciting new tuber's sweet taste and firmer texture makes old spuds seem pedestrian and ordinary. Sweet-potato fries have spread through Seattle like an epidemic, cropping up on menus at fancy places like Sazerac and Palisade, but some of the best and simplest in town can be found at King's Hardware and SMITH, because Linda Derschang's genius lies in recognizing a good thing when she sees it and leaving it alone. Here, the sweet potato is treated like an ordinary kitchen citizen, served in an unceremonious heap like regular fries, generously salted, and just on the right side of greasy.—Anna Roth