This recipe is more a method than a specific formula. The first version I saw of this was at Peas and Crayons Blog. I've altered it to suit our tastes, and every time I make it, it's a bit different.
You can build this "stack" with many different ingredients and quantities, depending on what you like and what you have on hand. What I've listed here are the items we most generally use.
Taco meat, prepared according to seasoning packet. You can also use shredded chicken, or beef. (Vegetarian version – substitute cooked brown rice for animal protein.)
Onions, garlic, cabbage, sliced thin and sauteed. Season with cumin to taste.
Can of refried beans, mixed with jar salsa until desired thinness.
½ can black beans, drained.
½ can corn, drained.
Shredded lettuce, diced red pepper, chopped tomatoes, and ½ can black olives, drained and chopped. Sour cream, diced avocado or guacamole (if desired.)
Spray baking pan with Pam. Lay one tortilla on pan. Spread on about 1/3 of all these ingredients: refried beans, black beans, the meat/rice, the onion mixture, the corn, and the cheese.
Lay another tortilla on top. Repeat the layering sequence until all of these ingredients are used. (Reserve some cheese for top.)
On last (top) tortilla, spread some salsa to keep top layer moist. Top with cheese. Bake in 325 degree oven until the stack is warmed through and the cheese is melted, 20-25 minutes. Remove from oven and top with lettuce, red pepper, tomatoes, and olives.
Dollop with sour cream/avocado/guacamole, if desired.