Preheat the oven to 350°F (175°C). In a skillet over medium heat, cook the ground beef until browned. Drain excess fat.

Add the taco seasoning, black beans, and refried beans to the skillet. Stir well to combine and heat through.

In a 9x13 inch baking dish, spread a layer of the meat mixture.

Layer half of the tortilla quarters on top of the meat, followed by half of the salsa and half of the cheese.

Repeat the layers, finishing with the remaining cheese on top.

Cover the dish with aluminum foil and bake for 20 minutes. Remove the foil and bake for an additional 10 minutes, or until the cheese is bubbly and golden.

Let the casserole cool for a few minutes before serving. Top with shredded lettuce, diced tomatoes, olives, and a dollop of sour cream.