STEP 1: Prepare the Chicken and Mushroom Filling

Start by heating 2 tablespoons of olive oil in a large skillet over medium heat. Add the diced onion and minced garlic, sautéing until fragrant and softened, about 3 minutes. Add the sliced mushrooms and cook until they release their moisture and become tender, about 5 minutes.

Next, add the shredded chicken breasts to the skillet along with dried thyme, salt, and pepper. Stir to combine, and then pour in the chicken broth (or white wine, if you prefer). Let everything simmer for about 5-7 minutes, allowing the flavors to meld together. Remove the skillet from heat and set aside.

STEP 2: Make the Béchamel Sauce

In a medium saucepan, melt 1/4 cup of butter over medium heat. Once the butter is melted, whisk in the 1/4 cup of flour, stirring constantly to create a smooth roux. Continue to cook for about 2 minutes to eliminate the raw flour taste.

Slowly add the 4 cups of whole milk, whisking constantly to avoid lumps. Cook the mixture over medium heat, whisking frequently, until it thickens, about 5-7 minutes. Once the sauce has thickened, add the garlic powder, onion powder, nutmeg, and salt and pepper to taste.

Once the sauce has thickened, remove from heat and stir in 1 cup of grated Parmesan cheese until smooth and creamy. The cheese will melt into the sauce, making it extra rich and flavorful. Set the béchamel sauce aside.

STEP 3: Assemble the Lasagna

Preheat your oven to 375°F (190°C). Lightly grease a 9×13-inch baking dish with cooking spray or olive oil.

Start with a thin layer of the béchamel sauce at the bottom of the baking dish to prevent sticking. Next, place a layer of cooked lasagna noodles on top of the sauce. Over the noodles, spread about 1/3 of the chicken and mushroom filling evenly. Top with 1/3 of the béchamel sauce and then sprinkle with 1/3 of the shredded mozzarella cheese.

Repeat this layering process two more times: another layer of noodles, followed by the chicken and mushroom mixture, the béchamel sauce, and mozzarella cheese. Finish with a final layer of noodles, the remaining béchamel sauce, and a generous sprinkling of mozzarella and Parmesan cheese.

STEP 4: Bake the Lasagna

Cover the baking dish with foil, making sure it doesn’t touch the cheese to prevent sticking. Place the lasagna in the preheated oven and bake for 25 minutes.

After 25 minutes, remove the foil and continue baking for another 15-20 minutes, or until the top is golden and bubbly. The lasagna should be hot and the cheese melted and slightly browned.

STEP 5: Rest and Serve

Once the lasagna is finished baking, let it rest for about 10 minutes before slicing. This allows the layers to set, making it easier to serve and helping the lasagna hold its shape.

Serve the white lasagna with a side of fresh green salad, a few slices of garlic bread, and perhaps a glass of white wine, such as Chardonnay or Sauvignon Blanc. The creamy richness of the lasagna pairs perfectly with the acidity and freshness of a crisp white wine.