I use a 9 x 13 greased pan
Home cooks frequently make the mistake of using raw poultry directly in layered bakes, which releases too much moisture and leaves the surrounding starches waterlogged. Pre-cooking the chicken breast wrapped in foil at 325 degrees Fahrenheit for one hour traps the natural juices while concentrating the flavor. Retaining that released pan liquid is essential because it provides the hydration necessary to bind the condensed soups and sour cream into a cohesive, velvety sauce without diluting the intensity.
Building the casserole requires strategic layering to manage starch absorption. Tearing the tortillas into quarters allows them to act as structural sponges that soak up the mushroom and chicken soup mixture while maintaining distinct layers during portioning. Seeded and chopped jalapeños introduce capsaicin, which cuts through the high fat content of the cheddar and swiss cheeses. Bake the assembled dish uncovered at 350 degrees Fahrenheit for 35 to 45 minutes, watching for bubbling edges and a lightly browned cheese crown that signals complete heat penetration through the center.
Dietary adjustments are straightforward when working with this architecture. Gluten-free corn tortillas substitute directly for standard wheat variations without altering the structural integrity, provided they are layered securely between the moisture-rich soup and cheese matrices.