Heat a large, heavy (preferably cast iron) griddle or pan over medium heat. Place the tomatillos, garlic cloves, onion quarters and jalapeño on the hot surface and cook, turning once or twice, until charred in spots all over.

Place all of them into a food processor and add the salt, lime juice and cilantro. Puree smooth. Taste for more lime juice, salt or even some sugar--I find it easiest to test with a tortilla chip, as just tasting the salsa straight is often too strong.

Store in a sealed container in the refrigerator.