Step 1

Preheat the oven to 375 degrees F.

Step 2

Heat a large sauté pan over medium-high heat. When hot, add oil and then the onions, garlic, mushrooms, basil, oregano, red pepper flakes, and 1/4 teaspoon of salt. Sauté for 5 minutes or until the mushrooms soften while stirring occasionally. Make sure all of the liquid from the mushrooms has evaporated before moving to step 3.

Step 3

Stir in spinach; cook until wilted and all of its moisture has evaporated. Remove the pan from the heat and stir in the cooked chicken. Set it aside.

Step 4

In a small bowl make a slurry by whisking together 1/2 cup chicken stock with flour. It should be thick milky consistency. Set it aside. In a small saucepan, combine the remaining 1 1/2 cups chicken broth, milk, nutmeg, and 1 teaspoon of salt. Bring to a slow simmer over medium heat, stirring occassionally. Once the mixture starts to bubble up around the edges, add the slurry while whisking nonstop.  Simmer until thickened, about 5-8 minute, whisking occassionally. Stir in Parmesan cheese and then remove from heat.

Step 5

Pour 1/2 cup sauce into bottom of 10X10 square baking dish, top with 2 noodles, 1 cup chicken mixture, 1 cup sauce, and 1/4 cup mozzarella, making sure noodles are covered with sauce. You can even press them down lightly. Repeat 3 more layers with noodles, chicken, sauce, and cheese. Last layer will have slightly more sauce and remaining cheese on top.

Step 6

Cover baking dish with aluminum foil and bake for 25 minutes. Uncover and bake for 15 minutes longer. If desired, broil for 2-3 minutes for golden brown top. Let stand 15-20 minutes before cutting and serving.