Heat a large skillet over medium-high heat. Working in a couple of batches, heat the chiles in the skillet for about 15 seconds on both sides, pressing down on them with a spoon or spatula. Remove and when cool enough to handle, use a pair of scissors to cut away the stems and then remove as many of the seeds inside the pepper as possible (don't worry if you don't get all of them, you'll strain the liquid later).

Place the chiles in a large bowl and cover with about 4 to 5 cups of warm tap water. Place a small plate on top of the chiles to keep them submerged. Let them rest in the water for at least one hour.

Use a pair of tongs to transfer the soaked chiles to a blender. Add the chopped tomato, and garlic, and add about 3 cups of the chile soaking water. Securely place the lid on the blender and purée until smooth.

Back in your skillet, heat 2 tbsp of olive oil (or butter) over medium heat. Add the onions and sauté until they are soft, about 4 to 5 minutes.

Carefully pour the puréed chile mixture into the skillet with the onions. Stir and bring to a simmer. Add another cup of the soaking water and simmer for about 2 minutes.

Place a fine-mesh sieve or colander over a heatproof bowl and strain the sauce through it, using a wooden spatula to help it through.

Use a paper towel to wipe out the skillet. Add the remaining 2 tbsp olive oil (or butter) over medium heat. Stir in the flour and cook until fully absorbed, about 1 to 2 minutes.

Whisk in the strained sauce and stir in the oregano, cumin, garlic powder, salt, and pepper. Simmer until slightly thickened, about another 4 minutes. Set aside.

Preheat oven to 350°F.

Heat another large skillet over medium-high heat and add the turkey, green chiles, salt (½ tsp), and a quarter cup of the prepared enchilada sauce. Cook, stirring often, until heated through, about 4 to 5 minutes. Set aside.

Ladle enough of the sauce over the bottom of the dish just to cover it (not too much).

In a saucepan large enough to hold a tortilla, heat about 1 to 2 tbsp of vegetable oil over medium heat. Once hot, quickly pass a tortilla through the oil, flipping once. Tongs or a pair of forks help you do this. Take care not to tear the tortilla, but if you do, just grab another tortilla (or go with the torn one, it will still roll just fine). You'll need to add more oil as you continue to lightly fry the tortillas.

Quickly transfer the tortilla from the skillet into the pan with the sauce. Flip the tortilla a couple of times to coat it with the sauce. Place on one end of the prepared dish. Spoon about 2 tbsp of the grated cheese along the center of the tortilla, lengthwise. Add about 2 tbsp of the prepared turkey over the cheese. Bring the sides of the tortilla up and press them together, one side over the other. Gently turn the enchilada seam-side down and continue this process until your dish is full (usually about 8 enchiladas).

Ladle some more of the sauce over the tops of the enchiladas. Sprinkle more chopped onion over the sauce, and then sprinkle on the remaining cheese (about 1 to 1½ cups) over the enchiladas.

Bake for about 20 minutes, or until the cheese is melty and the sauce is just bubbling. Serve at once, topped with shredded lettuce and pico de gallo.