10 to 12 tomatillos, husks removed and cut in half
1/4 cup water
1/2 medium onion, quartered
2 cloves garlic
2 serrano or jalapeno peppers
2 tablespoons cilantro, chopped
1/4 teaspoon salt
Put water, tomatillos, and onion into a saucepan. Bring to a gentle boil and cook unconvered for 10 minutes or until the tomatillos are tender. In a blender, place the cooked onion, tomatillos, and any remaining water. Add the garlic, peppers, cilantro, salt, and the juice of 1 lime. Blend until all the ingredients are smooth. Refrigerate and serve.
Alternately you can roast the tomatillos under the broiler instead of boiling.