Veggie Enchilada Stacks with Roasted Tomatillo Sauce

For the tomatillo sauce:

1. Preheat oven broiler to low. Line a baking sheet with parchment paper or foil. (If using foil, spray with non-stick cooking spray.)
2. Arrange the tomatillos, serrano chiles, onions, and garlic cloves on the prepared pan. Place the pan in the oven and broil for 5-7 minutes, then turn each of the veggies over and broil again for an additional 3-5 minutes. There should be some charring and browning, but not burning. The tomatillos will start to burst open and release their juices. (If you prefer a milder sauce, remove the seeds and ribs of the serranos after they're done cooking.)
3. Transfer the tomatillos, onions, garlic and chiles to a food processor or blender. Pulse until finely chopped, adding a little of the pan juices if needed to thin it out a bit. The sauce should be thick and pourable—not too runny, or the enchilada stacks will end up soggy. Add salt to taste.

For the enchilada stacks:

1. Preheat oven to 400°F. Line a baking sheet with parchment paper and brush it with a small amount of olive oil.
2. Lay 6 of the tortillas on the baking sheet and brush the tops with a little more oil. Bake for about 10 minutes, or until golden and crisp. Move to a cooling rack and repeat with remaining six tortillas.
3. Meanwhile, heat a very large skillet over medium-high heat. Add 1 tablespoon of oil and let it heat for 15-30 seconds, until shimmering. Add the onion and bell pepper. Season well with sea salt. Cook, stirring frequently, lowering the heat if necessary, until the onions start to soften and turn translucent about 4 minutes. Add the garlic and cook for 30-60 seconds, then add the zucchini and corn. Continue cooking until the veggies are just tender about 3 minutes more. Transfer to a bowl.
4. Add the remaining 1 tablespoon of oil to the pan. Add the mushrooms and cook, stirring often, until they start to brown, about 6 minutes. Add a little water, if needed, to prevent them from sticking. Add all the vegetables back to the pan and stir well. Remove from heat, but keep them warm until you're ready to assemble the stacks.

To assemble:

1. Arrange four of the tortillas on the lined baking sheet. Top each one with about ⅓ cup of the vegetable mixture, 1-2 tablespoons of the tomatillo sauce, followed by ¼ cup of shredded cheese. Repeat with another layer of tortilla, vegetables, sauce, and cheese. Place the remaining tortillas on top of the stacks and drizzle each one with a spoonful of tomatillo sauce and ¼ cup of the remaining shredded cheese.
2. Bake for 15-20 minutes, or until cheese has melted and the edges of the stacks are golden brown. Garnish with fresh cilantro and serve.