Chicken Enchiladas with Red Chili Sauce

Chicken Enchiladas with Red Chili Sauce
recipe adapted from Cooks Illustrated

Sauce and Filling:
1 1/2 tablespoons vegetable oil or corn oil
1 medium onion ,chopped fine (about 1 cup)
3 medium cloves garlic , minced
3 tablespoons chili powder
1 tablespoon ground cumin
1/2 teaspoon table salt
2 teaspoons granulated sugar
1 pound boneless, skinless chicken thighs, trimmed of excess fat & cut into 1/4-inch-wide strips
2 cans tomato sauce (8 ounces each)
1/2 cup chopped fresh cilantro leaves
1 can (4 ounces) pickled jalapeños , drained and chopped (about 1/4 cup)
8 ounces sharp cheddar cheese , grated (2 cups)

Tortillas and Toppings:
10 corn tortillas (six-inch)
Vegetable cooking spray
3 ounces grated sharp cheddar cheese (3/4 cup)
3/4 cup sour cream
1 avocado , diced medium
5 leaves romaine lettuce washed, dried, and shredded
2 limes , quartered

FOR THE SAUCE AND FILLING:
Heat oil in medium saucepan over medium-high heat until hot and shimmering but not smoking, about 2 minutes; add onion and cook, stirring occasionally, until softened and beginning to brown, about 5 minutes.

Add garlic, chili powder, cumin, salt, and sugar; cook, stirring constantly, until fragrant, about 30 seconds.

Add chicken and cook, stirring constantly, until coated with spices, about 30 seconds.

Add tomato sauce and 1/4 cup water; stir to separate chicken pieces. Bring to simmer, then reduce heat to medium-low; simmer uncovered, stirring occasionally, until chicken is cooked through and flavors have melded, about 8 minutes.

Pour mixture through medium-mesh strainer into medium bowl, pressing on chicken and onions to extract as much sauce as possible; set sauce aside. 

Transfer chicken mixture to large plate; freeze for 10 minutes to cool, then combine with cilantro, jalapenos, and cheese in medium bowl and set aside.

Adjust oven racks to upper and lower-middle positions and heat oven to 300 degrees.

TO ASSEMBLE:
Place a stack of tortillas in the microwave uncovered and heat for 1 minute or until softened and pliable. Place one tortilla on a flat surface and add a heaping tablespoon of filling down the middle. Fold the sides of the tortilla over the filling to overlap and place the filled tortilla seam side down onto a 9×13 baking dish. Repeat and continue with the remaining tortillas until filling is used up.

Pour the strained sauce over the enchiladas and then sprinkle the cheese down the middle of the enchiladas.

Cover the baking dish with foil and bake in the preheated oven for 20-25 minutes or until heated through and cheese is melted.

Uncover and serve immediately, passing sour cream, avocado, lettuce, and lime wedges separately.