In a large pot, add the tomatillos, jalapeño peppers, onion, garlic, and salt. Pour just enough water into the pot to cover all ingredients, then bring the water to a boil.
Once the water in boiling, lower the heat to low then simmer the mix for approximately 10 minutes.
Remove the pot from the heat and pour into a blender. Add the cilantro then blend the ingredients and water until you reach your desired consistency.
Place the pot back on the stove over medium heat. Add 2 tablespoons of vegetable oil and allow the oil to heat.
Add the salsa verde back into the pot and bring the heat down to low. Simmer the salsa for 15 to 20 minutes until the salsa thickens.
Remove from heat and allow the salsa verde to cool to room temperature. Add salt to taste, then serve.
Keep the seeds in the jalapeño peppers for more spiciness. Remove the seeds if you want a little less spiciness.If you want a little smokiness, try blackening the tomatillos and jalapeño peppers under a broiler until lightly charred prior to boiling. It provides a nice rustic touch.