In a large skillet brown ground beef and onion. Drain. Add taco seasoning and stir in refried beans. In a separate bowl mix together the cream of mushroom soup and sour cream.
Spread ½ of the sour cream mixture onto the bottom of a casserole dish. Tear up 3 tortillas and spread them over the sour cream mixture. Put ½ of the meat and bean mixture on top of that. Add a layer of shredded cheese (add hot sauce is using). Repeat the layers.
Sprinkle cheese over the top and place into the oven and bake uncovered at 350 degrees for 20-30 minutes