Tomatillo

What it is

Tomatillos are relatives of tomatoes in the nightshade family. The round fruit commonly measures 2.5–5 cm (1–2 in) across, with pale yellow flesh and many small seeds. Green is the familiar colour, but there are yellow, red and purple forms too.

For a sharp green salsa, the useful stage is firm fruit that fills its husk. As green varieties change colour and soften, their tang fades. Purple and Purple De Milpa have a sweeter balance, with some tartness still there.

Where it comes from

Tomatillos come from Mexico and Central America. They were a staple for the Aztec and Maya, and remain a familiar market fruit in Mexico and the highlands of Guatemala. Their travels also reached India: they arrived in the 1950s and were grown in Rajasthan, in the northwest.

How it's eaten where it grows

In Mexico, salsa verde puts the tomatillo’s acidity beside green chiles. For a roasted version, the fruit, garlic and chiles cook on a comal, a flat griddle, until browned. Blending them with the cooking juices, then adding chopped white onion and cilantro, makes a sauce with some texture.

Roasting gives the fruit a sweeter balance; flecks of charred skin stay in the salsa. Before cooking, the papery husks come off and a rinse removes the sticky coating underneath.

How it's grown

Tomatillos grow as a warm-season annual, started from seed indoors and transplanted outside after frost. They need sun and soil that drains well. Their sprawling stems suit a cage or trellis, and the plants keep producing until the first frost.

Growing several plants helps them set fruit. Pollen exchanged between two different varieties gives better results than relying on one plant alone.

When and where you'll find it

In the US Midwest, the harvest usually begins in late July and continues until autumn frosts. Some grocery stores carry fresh tomatillos in the produce section, usually the bright green kind; farmers’ markets can have other colours too. Whole canned tomatillos and jars of salsa verde are other ways the fruit reaches shops.