Preheat oven to 350 degrees. Spray a 9 x 13-inch casserole with nonstick cooking spray for ease in cleaning.
Brown ground beef in a large skillet over medium heat. When the ground beef is about halfway browned, add the onion. Cook until the beef is browned and the onion is soft. Reduce heat to low. Add garlic and cook for 1 minute, stirring continuously. Drain any excess grease. Add 1 1/4 cups enchilada sauce, black beans, and green chiles; cook for 1-2 minutes while stirring to combine.
Spread 2 tablespoons of enchilada sauce on the bottom of the casserole dish. Layer 1/4 of the tortillas on the bottom, then spread 1/3 of the beef mixture, and 1/4 of each cheese. Repeat these layers two more times. Top with the last layer of tortillas, the remaining enchilada sauce, and the remaining cheese.
Cover the pan with foil and bake for 30-35 minutes or until the cheese is melted and the casserole is heated through. Cook covered for 5 minutes.
Toss avocado with lemon juice. Top the casserole with avocado, tomato, cilantro, and jalapeno.
NOTES
Both flour and corn tortillas work for this recipe.
You can use canned or jarred enchilada sauce; however, homemade is highly recommended because of the amazing flavor.
Feel free to swap out the toppings for what your family enjoys most. Other garnishes might include black olives, sour cream, green onions, jalapeno pepper, salsa, or shredded lettuce.
A Mexican cheese blend can be substituted for the cheddar cheese and the Monterey Jack cheese.
Pinto beans, navy beans, lentils, or black-eyed peas can be substituted for black beans, although they should all be precooked for this recipe.
This recipe tastes best right out of the oven. If reheating, cover the casserole with foil and place it in a 350-degree oven for 20-25 minutes. You can also reheat it in the microwave or toaster oven.
Store leftovers in an airtight container in the fridge for up to 3 days.
