The plant with the scientific name Physalis philadelphica bears the fruit that Mexicans refer to as tomate verde (green tomato). It belongs to the same Solanaceae nightshade family of the tomato. Tomatillos are also called husk tomatoes in English because the fruit is surrounded by a papery husk.
Buy them with the husks still on to guarantee freshness. You can store them in a paper bag in the refrigerator for up to three weeks. Tomatillos can turn yellow when ripe, but use them in cooking while they are still green and firm.
Tomatillos can be added raw in salads and to salsas such as… salsa verde! Use them in guacamole and other sauces. For something different, try roasting the tomatillos before adding them to the guacamole.