Green Hot Sauce (Salsa Verde)

Place the tomatillos, serrano peppers, onion, and garlic in a saucepan, and add enough water to go about half way up the tomatillos. Sprinkle the salt over the top, bring to a boil, reduce the heat to medium-low, and cook until the tomatillos are soft and have turned slightly brownish in color, 20 to 30 minutes. Add more water if needed to keep the mixture from burning as it cooks. Most of the water should be absorbed by the time everything is cooked. Pour the cooked vegetables into a blender, and blend until smooth, add cilantro and lime juice and blend again until smooth. Serve with you favorite Mexican meal.