This easy, crowd-pleasing dish is also a kid favorite. Toasting the tortillas before building the lasagna keeps them from getting soggy as the dish bakes. Feel free to mix things up with different beans, cheeses, or vegetables between the layers.
1. Preheat oven to 350°F. Toast tortillas on 2 baking sheets in oven 5 minutes, or until light brown, turning once.
2. Heat oil in saucepan over medium heat. Add onion, and sauté 5 minutes, or until soft. Stir in chili powder, ancho chile powder, and garlic, and cook 30 seconds. Add 11/2 cups strained tomatoes, beans, chayote, corn, and 1/2 cup water, and season with salt and pepper, if desired. Cover, and cook 10 minutes, or until chayote is tender.
3. Coat 2-inch-deep x 8-inch round baking dish with cooking spray. Spread 1/4 cup strained tomatoes in bottom of pan. Set 1 toasted tortilla in pan; top with 3/4 cup bean mixture and 1/4 cup cheese. Repeat layering 4 more times. Top with last tortilla, and spread remaining 1/4 cup strained tomatoes over top. Sprinkle with remaining 1/4 cup cheese. Bake 30 to 45 minutes, or until casserole is bubbly and cheese has melted. Let stand 10 minutes before cutting into 8 wedges.