Leeks

Look for firm stalks with crisp, tightly rolled white ends and dark green tops that stand up straight instead of flopping. Skinnier leeks (under 1.5 inches) are more tender and sweeter. I grab the thinnest ones in the bin every time since the giant ones tend to be woody in the middle. Store them unwashed in the crisper drawer, loosely wrapped, and they'll keep 7-10 days. Don't toss the dark green tops: bag them in the freezer for stock.

Leeks are what onions taste like after finishing school: all the sweetness, none of the bite. They reward low, patient heat, which turns them silky and sweet, while high heat scorches them bitter in under a minute. The biggest mistake happens before the stove even turns on. Grit hides deep between the layers, so split them lengthwise and wash like you mean it. Braised leeks in butter and white wine might be the most underrated side dish there is.