Salsa de Tomatillo Cocida

1 lb tomatillos, husks removed (about 8)
1 jalapeno, stem, seeds, and ribs removed (use 2 if you want to make it very hot)
1/2 cup of white onion (about 1/2 a large white onion; no need to chop, you're going to blend it)
1/2 cup of loosely packed cilantro (take off the big stems)
2 cloves of garlic, peeled
1 tsp of salt
3 cups of water or thereabouts

In a saucepan, bring the water and salt to a boil. Add the garlic, chiles, tomatillos, and onion and simmer uncovered for 8-10 minutes. Drain reserving liquid. Transfer the vegetables to a blender. Add the cilantro and a pinch of oregano. Puree briefly (adding liquid as necessary to make correct consistency - usually the tomatillos are watery enough and you don't have to add any liquid).