This recipe takes the main ingredients of classic enchiladas and bakes them into a layered casserole reminiscent of lasagna. Mexican cheese blend, pickled jalapeños and cumin gives the creamy, cheesy béchamel sauce that ties it together a nice kick. You can tailor the recipe to what you have on hand (chicken instead of beef, or Cheddar in place of Mexican cheese blend), and make and bake it in advance if you like: Store it in the fridge for a few days or freeze it for a few months.
For the queso béchamel: Melt the butter in a medium saucepan over low heat. Stir in the onion and pickled jalapeños if using and cook until fragrant, 1 to 2 minutes. Whisk in the flour. Slowly whisk in the milk, whisking until no clumps remain. Continue to cook, whisking frequently, until thickened, about 5 minutes.
Switch to a wooden spoon and stir in the cheese and cumin, season with a pinch each of salt and pepper and stir until the cheese is completely melted, 2 to 3 minutes. Transfer the sauce to a bowl, cover with plastic wrap, placing the plastic directly onto the surface of the sauce, and refrigerate while you prepare the enchiladas.
For the enchiladas: Preheat the oven to 375 degrees F.
Roast the poblano peppers, holding them with tongs, over an open flame on the stovetop until heavily blistered and charred, about 2 minutes per side (see Cook’s Note). Place the poblanos in a bowl and cover with plastic wrap. Let steam until cool enough to handle, 10 to 15 minutes.
When the peppers are cool enough to handle, cut in half and use the back of a knife or a spoon to scrape the seeds and the skin off the peppers. Roughly chop the peppers and set aside.
Heat a large skillet over medium heat. Add the beef and cook, breaking up the meat with a wooden spoon, until fully cooked, 5 to 7 minutes. Drain off any excess fat from the pan. Stir one 10-ounce can of enchilada sauce into the beef.
Pour 2 to 3 tablespoons of the remaining can of enchilada sauce over the bottom of an 8 1/2-by-11-inch baking pan. Layer tortillas over the bottom of the dish so it’s covered, overlapping as necessary. Spoon in half the beef mixture to cover, top with about 3/4 cup béchamel sauce, and sprinkle with half the poblano and 1/3 cup of the shredded cheese. Repeat the layers again, ending with a layer of tortillas.
Cover the top layer with enchilada sauce and sprinkle with the remaining 1/3 cup cheese. Bake until browned and bubbling, about 45 minutes. Remove from the oven, sprinkle with the crushed tortilla chips and bake for an additional 5 minutes.
Allow the casserole to cool 15 minutes before serving. Slice into pieces and serve with the toppings of your choice for diners to garnish their servings. Enjoy!
The poblanos can also be roasted on a sheet pan in a 450-degree-F oven for about 10 to 15 minutes, turning the peppers once or twice.