Heat a large skillet over medium-high heat. Add the ground beef and onion, and use a wooden spoon to crumble the meat. Add the cumin, oregano, chile powder and salt, and continue to cook until meat is cooked through and onions are translucent. Drain all about 2 tablespoons of grease from the skillet.

Add the flour and garlic, and continue cooking until flour is toasty and garlic is fragrant, stirring often, for about 2 minutes. Gradually add the chicken broth, stirring briskly with a spoon to incorporate. Bring mixture to a boil, and then reduce heat to medium. Simmer mixture for about 15 minutes, or until slightly thickened. Remove from heat and stir in the black beans.

Prepare a 9x13 baking dish with nonstick spray. Ladle a small amount of the meat mixture into the bottom of the pan. Then, add the following layers in this order...

An even layer of 16 of the tortilla quarters

1/3 of the meat mixture

1/3 of the shredded cheese

Repeat these layers for a total of three times.

Bake at 350 for 30 minutes, or until cheese is slightly browned and bubbly. Allow casserole to sit for 10 minutes before serving.