Follow the steps in order for the best result.
Begin by preheating your oven to 350 degrees F (175 degrees C).
In a large saucepan, melt the butter over low to medium heat. Add the chopped onion and minced garlic, cooking until they become tender and fragrant. Be sure to stir frequently to prevent burning.
In a large mixing bowl, combine the cream of chicken soup, the sautéed onion and garlic mixture, fat-free sour cream, garlic powder, onion powder, dried oregano, dried basil, ground black pepper, poultry seasoning, and 1/4 cup of the shredded Parmesan cheese. Mix well, then gently fold in all of the cubed cooked chicken.
Now it's time to assemble the lasagna. In a 9x13 inch casserole dish, start with a layer of 3 no-boil lasagna noodles, covering the bottom of the dish.
Spread half of the chicken mixture evenly over the noodles. Next, layer half of the sliced fresh mushrooms and half of the fresh spinach over the chicken mixture. Sprinkle 1/4 cup of grated Parmesan cheese and 1/4 cup of mozzarella cheese over the top of this layer.
Create a second layer by repeating the previous step: another layer of 3 noodles, followed by the remaining chicken mixture, mushrooms, and spinach. Sprinkle with another 1/4 cup of Parmesan cheese and 1/4 cup of mozzarella.
Top the second layer with the last 3 lasagna noodles. Spread the remaining 1 1/2 cups of shredded mozzarella cheese evenly over the entire top of the lasagna, followed by the reserved 1/4 cup of Parmesan cheese.
Once the layering is complete, cover the casserole dish tightly with aluminum foil. Ensure the foil doesn't touch the top of the lasagna to prevent sticking. Bake in the preheated oven for 25 minutes.
Carefully remove the foil and continue baking for another 15-20 minutes, or until the cheese is nicely browned and bubbly.
Remove the lasagna from the oven and let it stand for at least 10 minutes before serving. This allows the lasagna to set as the cheese cools, making it easier to cut. For even easier cutting, consider letting it set overnight in the refrigerator.
Before serving, sprinkle fresh parsley over the top of the lasagna for added flavor and visual appeal.
Optional tips: This recipe can easily be halved and baked in an 8x8 inch pan. It also freezes well, making it a great make-ahead meal!