10 small tomatillos, husks removed and discarded, rinsed, and cut in half
2 to 4 serrano chiles, stemmed, seeded, and veins removed
1 small white onion, half left intact and the other half minced
1 large garlic clove
1 Tbsp sea salt, plus more as needed
½ cup / 10g cilantro leaves, finely chopped
Combine the tomatillos, chiles, intact onion half, garlic, and salt in a medium saucepan. Add water just to cover and bring to a boil and then decrease the heat to maintain a simmer and cook until the tomatillos become more translucent and the chiles have faded from bright green.
Pour everything into a blender, including the liquid, and puree. Return the puree to the saucepan and simmer gently until reduced by about one-third. Add the minced onion and cilantro to the cooked salsa and stir to combine. Taste and add more salt if needed.
This salsa is excellent served hot or cold.
It can be stored in a sealed container in the refrigerator for up to 1 week.