Brown the ground beef in a large pan over medium heat and drain. Add the taco seasoning, mixing well, followed by the refried beans. Preheat the oven to 350 degrees F. In a mixing bowl, combine the cream of mushroom soup and sour cream. Spread half of this into the bottom of a very lightly oiled casserole dish. Tear 3 of the tortillas and place these over the sour cream/soup mixture. Place half of the beef/bean mixture on top of the tortillas. Add a layer of 3/4 of the cheese. Hot sauce on top of the cheese, if desired. Repeat steps until all ingredients have been used. Bake for 20 to 28 minutes, or until done.