1To make the sauce, pour boiling water over the ancho chiles and set aside. Warm the olive oil in a cast iron pan and sauté the onion and garlic until browned and tender. Drain the ancho chiles, and add the chiles to a blender along with the sautéed onions and the rest of the ingredients. Puree until smooth. Thin the sauce as needed with more broth. Taste and adjust the seasoning with salt and chile powder as needed. Set aside or refrigerate until ready to use.
2In a frying pan, warm 1 tablespoon of olive oil. Add the 1/2 yellow onion and sauté until browned and tender. Add the ground beef and cook, stirring to break up the meat, until browned and cooked through. Drain off any grease. Add 1/2 cup of the red chile sauce and stir well to combine. Remove from the heat and set aside.
3Preheat the oven to 375°F. Have ready a 9×13 dish. Spread 1 cup of the red chile sauce into the bottom of the dish.
4In the cast iron pan, warm the canola oil over medium-high heat. Fry the tortillas quickly and set aside to drain on paper towels. Blot dry.
5For each enchilada, add some of the beef mixture and a sprinkle of cheese, and roll up tightly. Place in the baking dish and repeat. (These can be prepped up to 1–2 hours ahead.) You should easily fit 12.
6Warm the remaining sauce. Pour the sauce over the enchiladas to generously coat them, then top with the remaining cheese. Bake, uncovered, until bubbly and heated through and the cheese is golden brown, 20 to 30 minutes. Let sit for 5 minutes before garnishing and serving.