Tomatillo (pronounced toe-mah-tee-yo), a primary ingredient in Latin American green sauce (salsa verde), means "little tomato" in Spanish — but these beauties pack a lot of flavor into their small containers. With a distinctly tart, almost lemony flavor, tomatillos enhance a broad range of dishes, from guacamole and appetizers to stews and steaks.

The fruit of the tomatillo grows within a soft, parchment-like husk that is sometimes forced open as it approaches mature size, usually between 1" to 2" in diameter. Tomatillos are almost always harvested and used while still green. A yellowish or sometimes purplish blush on the fruit itself — the husk can be pale green to light brown — indicates a ripeness that makes them less desirable for common uses.
Tomatillos are sometimes used to flavor rice and tenderize meat. By far the most common role is as a base for salsa verde, usually combined with onions, cilantro, garlic, lime juice and chili peppers.

If you're not going to use them immediately, keep the husks on and store in a paper bag in the crisper drawer of the refrigerator for up to three weeks — do not keep in an airtight container. Tomatillos freeze well. Simply remove the husks and place in a suitable container for freezing. When needed, take out the desired amount and thaw at room temperature.

from Whole Foods Market website

Recipes
Compiled by Retu.

Guacamole en Molcajete con Tomate Verde

• 2 ripe avocados
• 6 tomatillos
• 2 cloves of garlic
• 1 yellow or white onion
• 2 tablespoons of cilantro
• serrano chili as desired
• salt

1. Roast the chilies and tomatillos.
2. Grind up the garlic with the salt and chiles in a molcajete (mortar and pestal).
3. Once well ground, add the tomatillos, avocados and grind a little more.
4. To garnish the guacamole, put sliced onion and chopped cilantro on top. Serve immediately.

Tomatillo Jam
1 hour 20 minutes 20 mins prep

• 3 cups prepared tomatillos (about 1-3/4 lb tomatillos)
• 1/2 cup fresh lemon juice
• 7-1/2 cups sugar, measured into separate bowl (See tip below.)
• 1/2 tsp. butter or margarine (optional)
• 2 pouches CERTO Fruit Pectin

1. Bring boiling-water canner, half-full with water, to simmer. Wash jars and screw bands in hot, soapy water; rinse with warm water. Pour boiling water over flat lids in saucepan off the heat. Let stand in hot water until ready to use. Drain well before filling.
2. Finely chop or grind tomatillos. Measure exactly 3 cups prepared tomatillos into 6- or 8-quart saucepot. Add lemon juice.
3. Stir sugar into prepared tomatillos in saucepot. Add butter to reduce foaming, if desired. Bring mixture to full rolling boil (a boil that doesn't stop bubbling when stirred) on high heat, stirring constantly.
4. Stir in pectin quickly. Return to full rolling boil and boil exactly 1 minute, stirring constantly. Remove from heat. Skim off any foam with metal spoon.
5. Ladle quickly into prepared jars, filling to within 1/8 inch of tops. Wipe jar rims and threads. Cover with two-piece lids. Screw bands tightly. Place jars on elevated rack in canner. Lower rack into canner. Water must cover jars by 1 to 2 inches; add boiling water if needed. Cover; bring water to gentle boil. Process 10 minutes. Remove jars and place upright on a towel to cool completely. After jars cool, check seals by pressing middle of lid with finger. (If lid springs back, lid is not sealed and refrigeration is necessary.)