Add the chopped onion and ground beef to the skillet.
Cook until the beef is browned and fully cooked.
Transfer the beef mixture to a colander.
Rinse with warm water and allow it to drain.
Return the beef mixture to the skillet.
Add the diced tomatoes to the skillet.
Add the corn to the skillet.
Add the jalapeños to the skillet.
Add the black beans to the skillet.
Sprinkle the taco seasoning over the mixture.
Stir until everything is evenly mixed.
Reduce the heat to low. Simmer for 5 minutes.
Lightly coat a 2-quart baking dish with cooking spray.
Cut the corn tortillas in half.
Place 8 tortilla halves in the bottom of the baking dish, overlapping slightly.
Spoon half of the beef mixture over the tortillas.
Spread the sour cream evenly over the beef layer.
Place the remaining tortilla halves over the sour cream.
Spoon the remaining beef mixture on top.
Place the baking dish in the oven.
Bake for 25 minutes.
Remove the dish from the oven.
Sprinkle the cheese evenly over the top.
Sprinkle cilantro over the cheese.
Cover the dish and allow it to rest for about 5 minutes so the cheese melts.
Notes
Tips and Tricks
Layering - Overlap the tortillas slightly so the base holds together after baking.Draining the Beef - Rinsing the cooked beef helps keep the casserole from becoming greasy.Cheese Melting - Covering the dish after baking allows the cheese to melt evenly without overbaking.
Storing and Reheating
Refrigerator - Store leftovers in an airtight container in the refrigerator for up to 4 days.Reheat on Stovetop - Place a serving in a saucepan with 1 to 2 tablespoons water. Warm over low heat, stirring until heated through.Oven Reheat - Place portions in an oven-safe dish, cover, and warm at 325°F until hot.