Kale is a proud member of the cabbage family, which accounts for its rather strong, forward flavor that borders (and sometimes tips over into) bitterness. It grows in a bunch with the leaves fanning out from a central stem and with a rib running down the middle of each leaf. Those edible leaves vary in color from light green to nearly purple depending on the variety, though they are universally coarse, thick, and fairly tough.
There are two main kinds that we commonly find in the markets: curly leafed and dino kale. Curly leafed kale looks stuck a finger in an electric socket. The bright green leaves are sometimes curled so tightly it can be hard to chop them. This kind of kale tends to have a bright, peppery flavor that can become quite bitter.
Dino kale goes by many names. Among them are dinosaur kale, cavolo nero, black kale, and tuscan kale. This kale has longer spear-like leaves with a pebbled appearance and a dark, mottled green color. Its flavor is deep and earthy, less bitter than curly leafed with an almost nutty sweetness (or so I've found).
I've also seen a third kind of kale, Russian Red, popping up here and there at farmers markets and the more gourmet natural food stores. This kale has flat, fringed leaves that resemble oak leaves or large arugula leaves. The few times I've had it, I'm reminded of the outer leaves of a cabbage. They're sweet and mild but with an edge of pepperiness.
To prepare kale, cut out the center rib and chop the leaves into ribbons or bite-sized pieces. That center rib is edible, though fairly fibrous. Treat it like celery and chop it into bits to cook with a soup or a sauce. The leaves can be eaten raw, sautéed until wilted, simmered with a soup, or even roasted until crisp. There seems to be a sweet spot during cooking when the bitterness recedes and the kale's sweeter character comes through. Over-cooking makes the kale taste overly bitter and decidedly off-putting.
Ready to explore the world of kales a little more? Take a look at these great recipes:
• Kale Chips: How to Eat a Bunch of Kale in One Sitting
• Kale Salad with Quick-Pickled Watermelon Radishes
• Kale Salad with Apricots, Avocados, and Almonds
• Hearty Kale, Sausage, and Bean Soup
• Fried Egg and Kale Toast
• Artichoke, Kale, and Ricotta Pie
• Sausage Pizza Topped with Crispy Kale
What dish made you fall in love with kale?
Related: For the Cook's Table: Flowering Kale