10 dried California chiles, or other mild chiles, stemmed, split and seeded
5 cups peeled and diced butternut squash (1/2-inch dice)
2 tbsp sunflower, safflower or grape seed oil
1 clove garlic, peeled
1 tbsp unsalted tomato paste
1 tsp ground cumin
1 tsp dried oregano
1 tsp sea salt
Olive oil cooking spray
12 6-inch corn tortillas
1/4 cup crumbled queso fresco (TIP: If queso fresco is unavailable, crumbled reduced-fat feta or goat cheese are also good options.)
2 scallions, thinly sliced
In a large skillet on medium-high, add chiles in batches, and toast, turning occasionally, until blistered and darkened, 1 to 1 1/2 minutes. Transfer to a large bowl, cover with 5 cups water and set aside for 30 minutes. (TIP: To keep chiles submerged, place a plate directly over top chiles.)
Meanwhile, preheat oven to 375°F. In a large bowl, toss squash with oil. Arrange on a large, rimmed baking sheet and roast until tender, about 20 minutes.
Meanwhile, prepare enchilada sauce: Drain 2 cups water from chiles. Transfer chiles and remaining water to a blender, along with garlic, tomato paste, cumin, oregano and salt; purée. Transfer mixture to a medium saucepan. Bring to a boil, reduce to a simmer and cook for 10 minutes.
Transfer squash to a medium bowl and stir in about 1/2 cup enchilada sauce; keep oven on. Transfer remaining sauce to a round 8- or 9-inch shallow bowl.
Spray a 9 x 13-inch baking dish with cooking spray. Warm a small nonstick skillet on medium. Add one tortilla and cook until soft and pliable, 15 to 30 seconds per side. Dip tortilla in enchilada sauce to coat both sides, then transfer to baking dish. Arrange a scant 1/4 cup squash down center of tortilla. Roll up tortilla, enclosing filling, and place seam side down. Repeat with remaining tortillas and squash. Spoon remaining enchilada sauce over enchiladas and bake until heated through, 15 to 20 minutes. Sprinkle with queso fresco and scallions.