Preheat the oven to 400 degrees. Toss the tomatillos, onion, green chile peppers and garlic with 2 tablespoons olive oil and salt, to taste, on a rimmed baking sheet. Roast in the oven until the vegetables have browned well on all sides, for a total of about 30 minutes. Remove from heat and allow to cool slightly.

Remove the skins from the garlic cloves, then remove the stems and seeds from the chiles. If you like a spicy green enchilada sauce, go ahead and use those seeds.

Place the vegetables and all of the juices into a blender or food processor and process until smooth.

Place the tomatillo mixture, water or stock, salt and pepper to taste in a medium sauce pan. Bring to a boil, then reduce the heat to medium low and simmer until the sauce reaches the desired thickness, about 10 minutes. Stir in the chopped cilantro and lime juice, and adjust the seasoning as necessary. Enjoy!