Those aren’t super-sized scallions, they’re leeks! Having a very small bulb and a long white cylindrical stalk of superimposed layers that flow into green, tightly wrapped, flat leaves, these beauties have a flavor that is reminiscent of shallots but sweeter and more subtle.
Leeks are an excellent source of vitamin K, as well as manganese, vitamin B6, copper, iron, folate, and vitamin C. Additionally they serve as a source of vitamin A (in the form of carotenoids), dietary fiber, magnesium, vitamin E, calcium, and omega-3 fatty acids
Pale to dark green
Look for long, white, unwrinkled stalks with bright green leaves. Avoid leeks that are too large in diameter. The green tops should not be limp or yellowed.
Leeks will release an aroma that can be absorbed by other things in the refrigerator, so store tightly wrapped. Do not trim or wash before storing..