Preheat the oven to 350˚F.

Position a rack in the center.

In a large skillet over medium heat, add the oil and ground beef. Cook, breaking up the ground beef, until it’s browned, 4-5 minutes.

Add the onions, peppers, black beans, and green chiles. Continue to cook for another 5-6 minutes, until vegetables are softened, but not browned.

Add the taco seasoning, salt, pepper, and ¼ cup of water. Continue to cook until water evaporates and the seasonings are evenly distributed, another 3-4 minutes. Remove from heat.

Spray a quarter sheet pan (9 x 13-inch) with nonstick spray. Place 2 flour tortillas in the center so they slightly overlap, and then place 6 tortillas around the edge, all overlapping and hanging over the edge of the pan.

Add about ⅓ of the cheese to the bottom of the tortillas. Then spread out your cooked quesadilla filling all the way to the edges of the pan. Top with the remainder of the cheese.

Place 2 more tortillas in the middle and fold tortillas over the edges to cover the filling. Lightly spray the top of the quesadilla with cooking spray.

Place a second, slightly smaller, sheet pan or baking dish on top of the quesadilla with foil in between the quesadilla and sheet pan.

Bake for 20 minutes at 350˚ F. Then remove the top sheet pan and foil. Increase the temperature to 400˚F and bake for another 10-15 minutes, until the tortillas are very crispy.

When the quesadilla comes out of the oven, let it rest for at least 10 minutes before slicing and serving.