01 -
Set oven temperature to 350°F (175°C).
02 -
In a large skillet over medium heat, cook ground beef and onion until beef is thoroughly browned and no longer pink. Discard excess fat.
03 -
Stir taco seasoning and refried beans into the cooked beef mixture. Continue to heat until warmed through and well combined.
04 -
In a separate bowl, blend condensed cream of mushroom soup with sour cream until completely smooth.
05 -
Spread half of the sour cream mixture evenly on the bottom of a baking dish. Arrange a layer of flour tortillas over the mixture, tearing tortillas as necessary for complete coverage. Distribute half of the beef mixture over the tortillas and sprinkle with about 1 cup of shredded cheese.
06 -
Repeat layering with remaining sour cream mixture, additional tortillas, and the rest of the beef filling. Top with the remaining shredded Mexican blend cheese.
07 -
Place casserole in the preheated oven and bake for 20 minutes, or until cheese is melted and bubbling.