Heat the oven to 375F. Brown the beef hard and undisturbed for the first 3 minutes in a wide pan, then break it up and cook through.

Push the beef aside, saute the onion in the rendered fat, then stir in the taco seasoning for 30 seconds before adding the salsa and tomato sauce.

Fold in the beans and corn and simmer 5 minutes until the mixture is thick, not saucy. A wet filling makes a sliding lasagna.

Spread a thin smear of the meat sauce in a 9x13, then layer: tortilla halves overlapping, a third of the filling, a quarter of the cheese. Repeat twice.

Top with a final tortilla layer, the last thin coat of filling and the remaining cheese.

Bake uncovered 20 to 25 minutes until browned and bubbling at the edges.

Rest 10 minutes before slicing. Serve squares with sour cream and cilantro.