Rinse the husked tomatillos well under running water to remove the sticky film on their skins — left on, it turns the sauce bitter. Add the tomatillos, jalapeños, garlic, and water to a saucepan.
Bring to a boil, then lower the heat and simmer until the tomatillos turn from bright green to a dull olive color and are soft enough to pierce easily with a fork.
Start checking around 15 minutes — the original timing calls for a full 30, but tomatillos are usually done well before that, and the extra time mutes the tang that makes this sauce worth making.
Transfer everything to a blender and puree until smooth.
Add the cilantro and puree again, just until incorporated.
Notes
Nutritional information is automatically calculated using the WP Recipe Maker nutrition database and should be considered only an estimate. Actual values may vary depending on ingredient brands, product variations, substitutions, and portion sizes.