Method

• 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 the 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. Taste and adjust seasonings with more salt or taco seasoning, if desired.
• 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. It’s okay if there are some small holes in the top. If you want to perfectly cover them, you can cut apart a new tortilla and use it to patch the holes in the top of the quesadilla. 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. I like to use a sharp knife to cut through the top tortilla and then use a bench scraper or pizza cutter to cut all the way through the quesadilla pieces. I try to cut the quesadilla into about a 3 x 5-inch rectangle to yield 15 large quesadilla pieces.
• Serve the quesadillas while warm with toppings. The quesadillas keep fine in the fridge for 4-5 days and reheat best in a 350˚F oven for 8-10 minutes until they are crispy and warmed through.