Tomatillo is Spanish for "little tomato," and it looks like a small green tomato. But it isn't. Tomatillos are fruit (originally cultivated by the Aztecs), a type of berry actually, that is part of the nightshade family (think potatoes, eggplant, sweet bell peppers, and tomatoes).

They have a sweet-tart flavor—an apple and lemon combined. Folks like to use tomatillos in salsa verde and serve this with pork or chicken entrees. But they can also be eaten raw just like their tomato cousins, which makes them a great addition to fresh salads. You can also stew, roast, grill, or sauté them.

Cooking is a good thing for them, though. It softens the thick skin that hides under its delicate paper-like husk, and the fruit's sweetness is enhanced.

While the peak season for tomatillos is May through October, they are available nearly year-round. Look for tight-fitting husks that cover firm, blemish-free flesh. Shriveled husks mean they're past their prime. When using, remove the husks and wash the flesh well—this removes the sticky the husks leave behind.

You can stock up on tomatillos because they have a longer shelf life than most produce. Store them in the fridge, husks on, in a paper bag up to two weeks, or without their husks up to one month.

You can also "quick-freeze" whole or sliced tomatillos on a parchment- or plastic-lined baking sheet; then transfer them to freezer containers or re-sealable plastic bags. They'll keep frozen for up to six months. And there are lots of good reasons to learn to use this fruit and keep plenty on hand. Consider:

• Tomatillos are low in calories—100g of berries = just 32 calories. By comparison, they contain slightly more calories, fat, and protein than tomatoes (100g tomato has 18 calories).
• They are loaded with dietary fiber, minerals, anti-oxidants and vitamins (A, C, and E).
• While they don't contain lycopene, they do contain a different kind of antioxidant phyto-chemical known as withanolide, Ixocarpalactone-A, which has anti-bacterial and anti-cancer properties.
• They are full of flavonoid anti-oxidants such as β-carotene, zea-xanthin and lutein. Consumption of natural vegetables and fruits rich in flavonoids helps protect from lung and oral cavity cancers.
• This fruit also has a great sodium-to-potassium ratio (0:6). Potassium is an important component of cell and body fluids, helps controlling heart rate and blood pressure.
• Further, the fruit has more minerals weight-per-weight basis than that in the tomato (copper, iron, phosphorous, manganese, and others.)

If you're interested in making your own salsa verde using tomatillos, here's ingredients and a few proportions (but remember the best salsa is always to taste). Combine 1 pound of tomatillos (husked) with 1/2 cup of chopped onion, minced garlic, 1 minced serrano chili pepper, cilantro, fresh oregano (I use about 1 tablespoon), and a little cumin and salt. Cook all this until everything is soft in 2 cups of water.

You may want to adjust the water-sometimes, I'm not sure why, this comes out a little runny.

Then puree the mixture slightly in your blender. This is amazing served with burritos or enchiladas.