SAUCE: Position a rack near the top of the oven. I use the highly preset, closest to the broiler. Preheat the broiler for about 10 minutes. If using fresh chicken, you can cook it at this time. Add the tomatillos, 1 whole poblano pepper, garlic, and quartered onions on a baking sheet and bake for 8-10 minutes turning halfway through. Remove the tray from the oven and immediately cover with a sheet of foil. This will allow the peels to loosen. Remove the peel from the garlic, poblano (remove the ribs and seeds), and tomatillos. Place the veggies into a food processor along with the cilantro, unroasted poblano (deseeded and ribbed), and baby spinach (if using) and blend until it breaks down into a sauce. Add the sour cream and chicken broth and continue to pulse until almost smooth, you can also add 1/4 teaspoon of cumin and season with salt and pepper to taste if desired.

CHICKEN: Bring a large pot of water to boil with a pinch of salt. Add the chicken to the pot, remove from heat and cover. Let cook for 25-35 minutes or until the chicken is poached and completely cooked through. Shred the chicken, set aside.

PIE: Cut the tortillas down the center. Preheat the oven to 375ºF. Place 4 pieces of the tortillas in a 9x9 baking dish. Don't worry if there's a little bit of space between the tortillas, that's okay. Add a layer of the chicken followed by 1/3 of the sauce and 1/3 of the cheese. Repeat the layers again. The final layer will have tortillas, then the sauce and finally the cheese.

BAKE: Bake the enchilada pie for 20-25 minutes or until the cheese melts. Sprinkle with cilantro and cotija cheese and serve with the lime wedges.