Salsa Verde

Remove the tomatillos papery husks and rinse to remove the sticky residue. Quarter the onion. Add all of the ingredients except the cilantro and salt to a large pot and just cover with water. Bring the water and ingredients to a boil and simmer for 10 minutes. Blend the cooked ingredients and the cilantro with the cooking water until smooth. (About 30 seconds). Heat 2 tablespoons of cooking oil in the pot. Pour the blended salsa back into the pot with the hot cooking oil Reduce the heat and simmer for 20 minutes. Add the salt and adjust as per the notes below, if necessary. Notes: Preparation: Too runny? Simmer until it has reduced to the desired consistency. Too thick? Add water, 2 tablespoons at a time, until the desired consistency is reached. Too picante or acidic? Add ONLY ONE of the following to reduce heat: 1/2 teaspoon baking soda, 1-2 teaspoons sugar, 1-2 teaspoons agave syrup. Like it hot? You do not ahve to seed the serrano chiles. Only seed them if you want to treduce the salsa's heat. Substitutions: Youcan substitute jalepeno chiles for the serranos; the flavor will be tasty, but won't be as bright. Storage: the salsa will keep in the refrigerator for 3 days. This salsa also freezes very well. Make a double batch so that you always have some on hand! Other names: You may also know this salsa as "green salsa" "green sauce" "verde salsa" or "tomatillo salsa".