Preparing the White Enchilada Sauce

Preheat your oven to 375°F (190°C). Lightly grease a 9×13-inch baking dish and set aside.

In a medium-sized saucepan, melt the butter over medium-high heat. Add the minced garlic and Serrano pepper, sautéing for one minute until fragrant.

Incorporate the flour into the mixture, stirring constantly to create a roux. Cook for two minutes to eliminate the raw taste of the flour.

Gradually whisk in the chicken broth, ensuring a smooth consistency. Season with cumin, salt, and black pepper, then bring the mixture to a gentle boil.

Once boiling, whisk in the sour cream and salsa verde. Stir in the chopped cilantro, remove the sauce from heat, and spread ¾ cup evenly across the base of the prepared baking dish.

Assembling and Baking the Enchiladas

Lay each tortilla flat and fill the center with shredded chicken, a portion of Monterey Jack cheese, diced onion, and avocado. Carefully roll the tortilla and place it seam-side down in the baking dish.

Pour the remaining sauce over the arranged enchiladas, ensuring even coverage. Sprinkle the reserved cheese over the top.

Bake in the preheated oven for 15-20 minutes or until the cheese is melted and bubbly. Allow the dish to rest for five minutes before serving.

Storage and Reheating Suggestions

Storage: Transfer cooled enchiladas to an airtight container and refrigerate for up to five days. Alternatively, tightly cover the baking dish with foil.

Reheating: Warm individual servings in the microwave in 30-second increments or reheat the entire dish in an oven preheated to 300°F (150°C) for 15-20 minutes.