1. Preheat oven to 450 degrees F. Place 1 tortilla on the bottom of a 7 to 9" round casserole dish. This will help keep all the ingredients together when serving. Use about 3/8 of the refried beans on this bottom layer.
2. Place another tortilla on top of that. Mix the rest of the refried beans with an equal or larger amount of salsa, depending on the size of your pan and how thick you want it. Spread just enough to cover the tortilla.
3. Continue process to the 4th tortilla (which also has the beans/salsa on it). Garnish the top layer with the lettuce first in a circle around the edge. You may want to wait for this until after you bake, as the lettuce may burn.
4. Add tomatoes, then in the very center, add black olives. Bake in the oven for about 20 minutes.
For an even better looking casserole, garnish the edges of each layer with tomatoes, lettuce, and olives, making the layers more visible from the side, and much more colorful!