Preheat oven to 350 degrees F. In a food processor or with a stick blender, puree the soup, green chilies, spinach, cumin, cilantro, sour cream, salt and pepper until smooth. Assemble the enchilada pie in an oiled 12-inch cast iron skillet or oven-proof casserole dish as follows:
a. Layer one cup of the soup mixture on the bottom of the pan.
b. Place 3 corn tortillas on top of the mixture, sprinkle with 1⁄4
of the shredded cheese and 1/3 of the green onions.
c. Repeat the process with 3 more layers of soup mixture,
tortillas, cheese and green onions.
d. Top with the remaining cheese.
Bake in the oven for 25-30 minutes. The sauce will be bubbly and
the cheese golden brown. Let rest for 10 minutes before slicing.