Remove stems, seeds, and veins from chile pods. Rinse well.
In a large pot, cover chiles with water and bring to a boil. Reduce heat, cover, and simmer for 20 minutes. Drain and let cool.
Blend half the chiles with 3 cups water, 3 tbsp flour, 2 garlic cloves, and ½ tbsp salt until smooth. Repeat with remaining ingredients.
Strain sauce through a fine sieve to remove bits of skin.
Heat olive oil in a saucepan. Add sauce and simmer for 10 minutes, stirring often. Set aside.
For step-by-step photos and tips, visit my full Authentic Red Chile Sauce Recipe.
In a separate skillet, heat canola oil and lightly fry tortillas until soft and pliable. Drain on a paper towel-lined plate.
Preheat oven to 350°F. Pour 1 cup of red chile sauce into the bottom of a 9x13-inch baking dish. Fill each tortilla with chicken, cheese, and onions. Roll up and place seam-side down in the dish.
Top rolled tortillas with more chile sauce and shredded cheese. Cover with foil (sprayed with cooking spray to prevent sticking). Bake for 20 minutes, or until bubbly and golden. Garnish with cilantro.
