Both of these humble, heroic vegetables are ancient (meaning they've been cultivated for a long, long time and, botanically, have been tampered with little over the millenia) "headless" members of the cabbage family. Neither of them has yet gained wide culinary acceptance in the United States (with the exception of the Southeast). This is changing now, with a broadening awareness of vegetable cookery in general, and of nutritional concerns in particular.

Nutritionally Speaking: Kale is a superstar! It is virtually loaded with calcium, potassium, indoles (cancer-fighting substances), beta-carotenes, and other antioxidants. Collards have the same nutrients, but in lesser concentration. Making friends with these two leafy greens is a good idea.

Culinarily Speaking: Kale, which is now available in many varieties, including purple, Russian, and "dinosaur" kale, is a very bitter green, and is most palatable when combined with other, sweeter ingredients, especially caramelized onions (my favorite kale companion). See the recipes for Bitter Greens with Sweet Onions and Sour Cherries and Kale Crunch.

Collard greens have a much softer, sweeter taste than kale. When you combine the two greens in the same dish, the mild collard flavor mitigates the sharpness of the kale.

Buying and Storing: Leafy greens are officially "in season" in the winter months, but tend to be available year-round. Choose leaves that are crisp and fresh and have a deep green color, with no yellow tinge. Smaller leaves have a milder flavor, can be cooked whole, and often have stems tender enough to eat. With larger leaves, you'll need to cut out and discard the stems, and then chop the leaves into small pieces.

Store kale and collard greens in dry plastic bags in the refrigerator for up to three days. You can also cook the greens, and store them in the freezer in sealed plastic bags. They'll keep for months, so you can use them spontaneously in soups or casseroles when you don't have time to get to the store.