Heat the oven to 400.

On medium heat, brown the meat with onions; drain. Drain the beans.

Stir in the salsa and beans into the meat mixture.

Wrap the 12 tortillas in a wet paper towel and microwave for 2 minutes until hot and soft.

Spray the bottom of a 9×13 pan. Lay 4 tortillas on the bottom of the pan (they will be overlapping).

Cover with the meat mixture, sprinkle with cheese. Layer with 4 more tortillas.

Spread 1/3 of the sour cream over the tortillas and repeat the method above (tortillas, sour cream, meat mixture, cheese), ending with cheese on the very top.

Cover with foil. Bake for 35-40 minutes or until casserole is heated through.

Let stand 5 minutes before serving. Garnish with shredded lettuce, tomatoes, and cilantro. Serve with Tabasco sauce.