In a skillet, brown the ground beef over medium-high heat. Drain off any excess grease.
Stir in the taco seasoning and cook according to package directions.
In a bowl, combine the refried beans, diced tomatoes and green chilies, and salsa. Mix well.
Spread half of the bean mixture in the bottom of a 9×13 inch baking dish.
Layer half of the tortilla wedges over the bean mixture.
Spoon the seasoned ground beef mixture evenly over the tortillas.
Top with the remaining tortilla wedges.
Spread the remaining bean mixture over the tortillas.
Sprinkle both cheeses evenly over the top.
Bake for 20-25 minutes, or until the cheese is melted and bubbly and the casserole is heated through.
Let stand for 5 minutes before serving. Serve with your favorite toppings.
Notes
For a make-ahead option, assemble the casserole, cover tightly, and refrigerate for up to 2 days. Bake as directed, adding a few extra minutes to the cooking time if baking from cold.
To freeze, assemble the casserole in a freezer-safe dish, cover tightly with plastic wrap and then foil. Freeze for up to 3 months. Thaw overnight in the refrigerator and bake as directed.
You can adapt this recipe for a slow cooker. Brown the beef and mix with taco seasoning. In the slow cooker, layer half the tortillas, then the beef, then the remaining tortillas. Top with the bean mixture and cheese. Cook on low for 4-6 hours or on high for 2-3 hours.