These meatless enchiladas blend cheese, a tomato and white-wine-based chile sauce, and chopped avocado on deep-fried tortillas.
Place chiles in saucepan; add water to cover. Bring to a boil. Reduce heat; simmer 5 to 10 minutes. Cool slightly, remove stems, and puree chiles and liquid in food processor.
Heat 1 tablespoon oil in a deep skillet over medium heat. Add onions, garlic, brown sugar, cumin, and oregano; saute until onion is soft, 4 to 5 minutes. Add wine, chile puree, tomatoes, and stock; simmer about 20 minutes, until thickened to stew consistency.
Peel, pit, and roughly chop avocados. Toss with cilantro, lime juice, salt, and pepper.
Heat oven to 400 degrees. Heat remaining 4 cups oil in a wide, heavy saucepan over medium heat until very hot but not smoking, 7 to 10 minutes. Using tongs, fry 6 tortillas, one at a time, for 2 to 3 seconds. Drain on paper towel-lined sheet.
Dip fried tortillas in chile sauce to lightly coat both sides. Spoon 2 tablespoons avocado filling on each tortilla; roll up. Spread 1/2 cup chile sauce into large, deep casserole. Arrange rolled tortillas seam-side down in casserole so they fit snugly; repeat entire process, covering bottom of casserole; pour 1 cup sauce over tortillas; sprinkle with half the cheese. Make a second layer using remaining ingredients. Top with remaining sauce and cheese.
Bake enchiladas until heated through, 25 to 30 minutes. Serve immediately.
Ancho chiles are available at specialty-food stores and many supermarkets.