You have probably seen them in the produce section of your local grocery store and wondered what they were. Usually the ones available in the grocery store look like small green tomatoes with lantern shaped paper husks around them. At the same time, because the name sounds similar, when asked if they have tomatillos, some that are unfamiliar with them may confuse them with tommy toe, which is a variety of cherry tomatoes. While they are related to the latter, tomatillos are a different fruit altogether. To make it even more confusing, in most of Mexico they are known as tomate verde, or green tomato.
They are native to the Americans, but are not widely adopted into other cuisines after the Spanish conquistadors returned home from the New World. Perhaps because of this, there are now only a few varieties of this fruit and the plants producing them remain about half wild. In fact, one of the varieties is called Tomatillo de Milpa, and are grown wild in the cornfields of Mexico.
They have a tangy, citrus like flavor. They are also related to the ground cherry and just like the latter, they can be eaten raw, but are usually cooked, which brings out the best flavor. They are principally used in Mexican salsas. Salsa verde, usually gets its green color from the use of this fruit.
When buying them, it is best to pick those ones that have completely filled their paper husk, they are not fully mature if they haven't. The average size is about one and a half ounces. Larger ones have less flavor and can be a little bitter. If they stay on the plant long enough, some of them will soften a little and turn a little yellowish. These seem to be a little sweeter and have a fuller flavor. However, they are normally picked and used when they are green and firm. It's also sometimes possible to find purple blushed ones. These are said to have a rich and herbal flavor. They can be stored in the refrigerator without a loss of flavor. In fact, if they are kept loose in the vegetable drawer, they will keep fresh for at least three weeks in the refrigerator.
Many Mexican cooks suggest boiling them. This seems to produce a blander, almost watery salsa. The natural sweetness of this fruit can be brought out better by roasting. The traditional way is on a cast iron griddle, but this can make a sticky mess. An easier way of roasting them is on a cookie sheet under the broiler. After they turn black on top, they are turned and roasted on the other side. For a simple salsa, while they are roasting under the broiler you can roast some garlic and jalapeno or serrano chilies in a cast iron griddle. Just throw the peppers and garlic cloves into a hot dry skillet and cook until they soften and begin to blacken a little, turning them occasionally. After everything is roasted, simply remove the stems from the chilies and the papery skins from the garlic and transfer everything to a blender or food processor. Add salt as per your taste and you're done.
So the next time you're making Mexican food, or ordering it in a restaurant, why not try some green salsa and see what you've been missing.