Make the enchilada sauce: In a medium pot over medium heat, combine the oil, onion, a pinch of salt and a few grinds of pepper. Cook until the onion is tender, about 6 minutes. Raise the heat to medium high and add the tomato paste; stir with a wooden spoon and cook until it deepens in color, 3 minutes. Add the garlic, cumin and thyme. Cook, stirring, until combined and fragrant, about 1 minute, then add the crushed tomatoes and beef broth. Bring to a boil, then reduce to a simmer and cook, covered, for 20 minutes. Cover and keep warm over low heat.
Cook the beef: Preheat the oven to 350 degrees F. In a large straight-sided pan, heat the olive oil over medium-high heat. Add the onion and green and red bell peppers. Sprinkle with a nice pinch of salt and cook until the onion and peppers are tender but not browned, about 6 minutes. Add the garlic and cook until fragrant, about 1 minute more. In this order, add the beef, onion powder, cumin, thyme, Sazon, tomatoes and broth, allowing time between each addition to stir and blend. Cook for another 8 to 10 minutes, stirring to break down the beef into bits. When the beef is cooked through, taste and season with a pinch of salt and a grind or two of pepper. (Sazon adds salt, so be careful not to over-season.) Set aside.
Prepare the chicken layer: In a large bowl, toss together the shredded chicken, 1/2 cup of the enchilada sauce and the cheddar and pepper jack cheeses. Set aside.
Assemble and bake the casserole: Use the butter to coat the bottom and sides of a deep 13-by-9-inch baking dish. In a small bowl, toss the shredded cheeses together. Pour 1 cup of enchilada sauce into the prepared dish. One at a time, dunk the tortilla slices in the still-warm enchilada sauce in the pot and layer them on the bottom of the dish using the straight edges to line the sides, overlapping where needed and covering the entire bottom of the dish. Next, add 1/2 cup of the shredded cheese blend, all of the beef, another 1/2 cup of the shredded cheese blend, a new layer of tortillas dunked in the enchilada sauce, all of the chicken and a final layer of tortillas dunked in the enchilada sauce. Pour the rest of the sauce over all of the layers and top with the remaining shredded cheese blend. Bake until the cheese is melted and the sauce bubbles, about 30 minutes. Let it rest a bit before you slice it, just like lasagna.
Photograph by David Malosh
Recipe courtesy Sunny Anderson for Food Network Magazine