1 Brown the ground beef: Heat 2 tablespoons olive oil in a large sauté pan or cast iron frying pan on medium high heat. Add the ground meat, breaking it up as you add it.
Sprinkle with salt. Sprinkle on the chile powder, cayenne, cumin, and coriander. Increase the heat to high. Add another 2 tablespoons of olive oil.
Do not stir the meat unnecessarily. Allow the meat to brown on one side, and then stir it so the other side can be browned.
As soon as the meat is browned, remove the pan from the burner. The meat will continue to cook in the heat of the pan.
Once you are sure that the meat is cooked through, use a slotted spoon to remove the meat from the pan to a bowl. Set aside.
2 Sauté onions, bell peppers, garlic, add tomatoes, chiles, oregano: Add another tablespoon of olive oil to the empty pan used to cook the meat and set over medium heat.
Add the onions and chopped bell peppers. Cook until onions have softened, about 5 minutes. Add the garlic, cook for an additional 1 minute.
Add the diced tomatoes, green chiles and oregano. Bring to a simmer. Simmer gently for 15-20 minutes while you prepare the tortillas.
3 Cook the tortillas: While the sauce is simmering, soften the tortillas by frying them in a little oil. In a 9-inch skillet, heat 1/2 cup olive oil on medium high heat until it is sizzling hot, but not smoking.
Cook the tortillas one at a time, for 5 seconds on each side, so that they soften, but don't get crisp.
Remove the tortillas with a metal spatula or tongs and place on a plate lined with paper towels to soak up the excess oil.
4 Preheat oven: Preheat oven to 350°F and lightly oil a 9x13-inch glass or ceramic baking dish.
5 Assemble the casserole: In baking dish, arrange 4 tortillas in one layer, overlapping slightly (tortillas will not cover bottom completely).
(If you don't have time to pre-soften the tortillas, coat the bottom of the pan with some olive oil and spread a little sauce over the bottom before adding the tortillas.)
Spread half of bean mixture evenly over tortillas in dish and top with half of meat mixture. Sprinkle one third cheese over the meat and spread half of the sauce over the cheese.
Repeat layering of tortillas, beans, meat, cheese, and sauce and top with remaining 4 tortillas. Sprinkle remaining cheese over tortillas.
6 Bake: Bake casserole on the middle rack in the oven at 350°F for 35 minutes, until the casserole is heated through and the cheese is completely melted and bubbling.
7 Cool and serve: Let the casserole stand for 10-15 minutes before serving.
Serve with sour cream, chopped avocado, chopped cilantro, and thinly sliced iceberg lettuce on which has been sprinkled vinegar and salt.