Created by JostLori on August 7, 2015
Step 1: Bring stock and chiles to a boil in a 4-qt. saucepan over medium-high heat; cook until chiles are soft, about 10 minutes. Remove from heat and set aside.
Step 2: Heat 2 tbsp. oil in a 10" skillet over medium-high heat. Add 2/3 of the onion, and cook until soft, about 5 minutes. Transfer to a blender along with chiles and 1 cup cooking liquid, and garlic, and purée until smooth; set aside.
Step 3: Heat 2 tbsp. oil in a 12" skillet over medium heat. Add flour, and cook, stirring, until smooth, about 2 minutes. Add chile purée, remaining cooking liquid, cumin, and oregano, and season with salt and pepper; reduce heat to medium-low, and cook, stirring often, until sauce thickens, about 30 minutes. Keep sauce warm over low heat.
Step 4: Heat oven to 400°. Heat remaining oil in a 10" skillet over medium heat. Add 1 tortilla, and fry, turning once, until pliable, about 5 seconds. Using tongs, transfer tortilla to sauce, and turn to coat completely, letting excess drip back into skillet. Transfer to a large plate, and scatter with 1⁄4 cup cheese; roll tortilla around cheese into a tight cylinder, and transfer to a 9"x13"baking dish, seam side down.
Step 5: Repeat process with remaining tortillas and 2 3⁄4 cups cheese.
Step 6: Pour remaining sauce over enchiladas and sprinkle with remaining cheese and onions; bake until cheese melts and enchiladas are hot, about 10 minutes.
Step 7: Serve with a dollop of sour cream or crema fresca (optional).