2 teaspoons olive oil
1 onion (medium, chopped)
2 garlic cloves (minced)
3 yellow banana chile peppers (seeded, deveined and minced)
3 pounds mushroom (sliced)
1/4 teaspoon salt
1/2 teaspoon oregano leaves (dried)
1 can enchilada sauce (14 ounce, preferably green)
8 corn tortillas (6-inch, cut in half)
2 packages frozen chopped spinach (10 ounces, thawed)
6 1/2 ounces reduced-fat Monterey jack cheese (grated)
1. Heat oil in a very large non-stick skillet. Add onion, garlic and peppers and stir. Add mushrooms and cook about 15 to 20 minutes, until liquid evaporates. (If pan is not large enough, cook mushrooms in batches.) Add salt and oregano.
2. Preheat the oven to 350 degrees F. Spread half of the enchilada sauce into a 13x9-inch baking dish.
3. Arrange 8 tortilla halves over the sauce in the baking dish. Drain the spinach, squeeze it dry and mix it thoroughly with the mushroom mixture. Spoon half the mushroom mixture into the baking dish, carefully covering tortillas.
4. Set aside 1/4 cup (about 1 ounce) of grated cheese. Sprinkle the rest of the cheese on top of the mushroom mixture. Layer with the remaining 8 tortilla halves, then the remaining mushroom mixture and enchilada sauce. Sprinkle top of casserole with the remaining 1/4 cup cheese.
5. Cover baking dish with foil and bake for 30 minutes, or until casserole is steaming hot in the center.