1. Preheat the oven to 350F. Prepare a 9x13 casserole dish by coating lightly with non-stick spray.

2. Cut the onion and bell pepper into small cubes. Rinse and drain the black beans. Slice the green onions (both green and white portions). Pull the cilantro leaves from the stems and give them a rough chop. Combine the onion, bell pepper, beans, mushrooms, green onions, cilantro, and diced green chiles in a bowl. Add ¼ tsp salt; stir until evenly combined.

3. Toast the tortillas in a dry skillet to crisp them up. 

4. Chop the tortillas into halves.

5. Build the casserole as layers of, from the bottom: sauce, tortilla, vegetable, sauce, cheese:

• Spread ½ cup of the sauce in the bottom of the dish. 
• Arrange 3 or 4 of the tortillas over the sauce.
• Cover tortillas with a third of the vegetable mixture.
• Drizzle ½ cup of the sauce over the vegetables.
• Top with 1 cup cheese. 

​    Repeat these layers two more times, or until the vegetable mix, sauce, and cheese are gone.

6. Bake the casserole for 40-45 minutes, or until the edges are bubbly and the cheese just begins to brown on top. Slice into six portions and top with extra green onions and cilantro, if desired.