Kale, a hearty cold-weather green, is a nutritional powerhouse. It has frilly blue-green leaves, a nice toothsome texture that doesn’t go all mushy in the blink of an eye, and, most important, it has a pleasant, earthy flavor with just the faintest bitter bite.
Kale is like cabbage with an attitude: a little peppery, a little sweet, with a slight mineral edge, perhaps, but none of the metallic quality of spinach. It's fall and winter vegetable whose flavor becomes sweeter and mellower when the weather turns chilly.
You’ll find three basic types of kale in markets: Scotch kale which has ruffled, dark green (sometimes almost blue) leaves; Russian kale, which is smaller, flatter, sweeter, and has more tender leaves; and Tuscan or black kale (also known as cavolo nero, Lacinato, or dinosaur kale), which has elongated, very dark green leaves that have a pebbled texture. The latter is sometimes labeled cavolo nero, which means “black cabbage” in Italian. Scotch kale is what you’re most apt to find at the grocery store, while the other two types are rarer and more likely to be sold at farmers’ markets or specialty food stores.
Kale is usually sold in bundles. Choose deeply colored leaves, with no signs of yellowing or bruising.
Wash kale in a deep sink or a very large bowl of cold water, gently swirling the stalks to encourage any soil or grit to disperse into the water. Shake off the excess water and pat dry with paper towels. Before cooking kale, you’ll need to remove the tough stems and central ribs from all but the smallest leaves. You can cut them out with a knife or simply tear away the leaf from the rib.
Tiny, fresh kale leaves can be tender enough to eat raw in salads, but cooking kale with some liquid yields nicely tender results. Kale’s hardy texture requires more cooking time—a good 15 to 20 minutes—than do spinach or other tender greens that wilt quickly. Braising, steaming, and simmering in soups are among the best cooking methods for kale. Cooked kale also makes an excellent ingredient for dishes like creamy gratins and rich savory tarts.
Store kale unwashed in an unclosed plastic bag in the refrigerator’s crisper drawer, where it keeps well for two or three days. If you need to store it longer, wrapping the bundle in slightly damp paper towels before putting it in a plastic bag helps prolong its freshness. But try to use kale within five to seven days, because the longer you keep it, the stronger its flavor will become.