Step 1

Turn your broiler on high. Arrange the tomatillos, onion and garlic on a baking sheet and set under the broiler until about halfway charred. Keep an eye on it, as this can take anywhere from 5 minutes for dryish tomatillos to 15 for wet ones.

Step 2

Meanwhile, char the serranos over a gas burner, holding them with tongs. This is a better method for charring your serranos because they don't cook fully this way, but if this bothers you, put the serranos under the broiler with everything else.

Step 3

Remove the garlic and peel it when it's cool enough to touch. Remove the skins and seeds from the serranos. Move everything into a blender, along with all the other ingredients. Puree. Add salt to taste.