Mexican Quesadilla Casserole

Directions
Preheat the oven to 350 degrees F (175 degrees C). Spray a 9×13-inch baking dish with cooking spray.

Heat a large skillet over medium-high heat. Cook, stirring beef and onion in the hot skillet until beef is completely browned, 5 to 7 minutes. Drain and discard grease.

Stir tomato sauce, black beans, diced tomatoes, corn, and chopped green chiles into ground beef mixture. Season with chili powder, cumin, garlic, oregano, and red pepper flakes. Reduce heat to low and simmer for 5 minutes.

Spread about 1/2 cup beef mixture in the bottom of the prepared baking dish. Top with 3 tortillas, overlapping as needed. Spread another 1/2 cup beef mixture over tortillas. Sprinkle 1 cup Cheddar cheese over beef. Layer the remaining tortillas, beef mixture, and Cheddar cheese as above.

Bake in the preheated oven until cheese melts and mixture is heated through, about 15 minutes. Cool 5 minutes before serving.