The All-Raw Version

1. Roughly chop the tomatillos and the chiles;
2. In a blender or food processor, combine the tomatillos, chiles, cilantro and 1/4 cup water;
3. Process to a coarse puree, then scrape into a serving dish;
4. Rinse the onion under cold  water, then shake to remove excess moisture;
5. Stir into the salsa and season with salt, usually a generous 1/4 teaspoon.

The Roasted Version

1. Preheat a broiler;
2. Roast the tomatillos and chiles on a baking sheet 4 inches below a very hot broiler until darkly roasted, even blackened in spots, about 5 minutes;
3. Flip them over and roast the other side, 4 to 5 minutes more will give you splotchy-black and blistered tomatillos and chiles;
4. In a blender or food processor, combine the tomatillos and chiles, including all the delicious juice that has run onto the baking sheet;
5. Add the cilantro and 1/4 cup water, blend to a coarse puree, and scrape into a serving dish;
6. Rinse the onion under cold water, then shake to remove the excess moisture;
7. Stir into the salsa and season with salt, usually a generous 1/4 teaspoon.