Preheat your oven to 350℉. This ensures that your White Chicken Enchiladas bake evenly and thoroughly, resulting in perfectly melted cheese.
Spray a 9×13-inch baking dish with nonstick spray. This will help prevent the enchiladas from sticking to the dish, making cleanup easier.
In a large bowl, stir together the shredded chicken, enchilada sauce, 1 cup cheese, green chiles, and optional onion. Mixing these ingredients thoroughly will ensure that every bite is packed with flavor.
Take a tortilla and place 2-3 tablespoons of the chicken mixture down the center. It’s important not to overfill the tortillas to prevent them from tearing while rolling.
Roll the tortilla tightly to close, ensuring the filling is secure inside. Repeat this process for all 10 tortillas.
Place the rolled tortillas seam side down in the greased baking dish. Arrange them neatly to ensure even cooking.
In a medium saucepan, melt the butter over medium heat. Once melted, whisk in the flour until smooth. This will create a roux, which is key for thickening the sauce.
Pour in the chicken broth and whisk to combine. Allow this mixture to simmer and thicken for 2-3 minutes. Stir frequently to prevent sticking.
Slowly stir in the sour cream and remaining green chiles. If you are using low-fat sour cream, it’s wise to temper it by mixing in a bit of the warm broth first. This prevents curdling.
When the mixture is bubbling, stir in 1 cup of cheese and mix until melted and smooth. You want a creamy sauce that will adhere to the enchiladas.
Pour the cheese sauce over the enchiladas in the baking dish, ensuring they are fully covered. This will create a deliciously cheesy crust as they bake.
Top the enchiladas with the remaining ½ cup of cheese. This additional layer will melt beautifully, creating a golden topping.
Bake in the preheated oven for 25 to 30 minutes, or until bubbly and slightly browned. Keep an eye on them to avoid overcooking.
Once done, remove from the oven and garnish with chopped fresh cilantro, if desired. This adds a pop of color and freshness to your dish.