In a spacious skillet, heat a drizzle of olive oil over medium-high heat. Add diced onion and minced garlic, sautéing until fragrant and translucent, about 3–4 minutes. Toss in sliced white mushrooms and cook until softened, around 5 minutes, followed by fresh spinach until wilted. Remove from heat and gently fold in the shredded chicken for a delicious filling.

In a medium saucepan, combine chicken stock, whole milk, a pinch of nutmeg, and salt. Bring this mixture to a gentle simmer over medium heat. As it warms, gradually whisk in all-purpose flour, stirring until thickened, roughly 5–7 minutes. Finally, mix in grated Parmesan cheese, allowing it to melt into a creamy sauce perfect for your White Chicken Lasagna.

Preheat your oven to 375°F. In a greased baking dish, pour half of the creamy sauce to cover the bottom. Layer with no-boil lasagna noodles, followed by the chicken and vegetable mixture. Pour in more sauce, then sprinkle with mozzarella cheese. Repeat the layering process, finishing with a final layer of noodles and sauce, topped generously with mozzarella.

Cover the baking dish with foil, ensuring it doesn’t touch the cheese, and place it in the preheated oven. Bake for 25 minutes to allow the lasagna to cook through. Afterward, remove the foil and bake for an additional 15 minutes.

Once baked, remove the lasagna from the oven and let it rest for 15-20 minutes. This resting period helps the layers set, making it easier to slice. When ready, cut into squares, serve warm, and enjoy a cozy dinner full of flavor and comfort!