Preheat your oven to 350°F (175°C). While the oven is heating up, boil the lasagna noodles according to the package instructions until they’re al dente. Once cooked, drain them and set them aside.

In a large skillet, melt the butter over medium heat. Add the minced garlic and sliced mushrooms, sautéing until the mushrooms are tender and any excess moisture has evaporated. Stir in the cooked chicken and season with salt and pepper to taste. Set the skillet aside while you prepare the Alfredo sauce.

Alfredo Sauce: In a separate saucepan, melt the remaining butter over medium heat. Gradually whisk in the flour to create a roux, cooking for about 1-2 minutes until it turns golden brown. Slowly pour in the heavy cream while continuously whisking to prevent lumps from forming.

Once the cream is incorporated, let the mixture simmer gently, stirring occasionally, until it begins to thicken. This should take about 5-7 minutes. Stir in the grated Parmesan cheese until it’s melted and the sauce is smooth and creamy. Remove the saucepan from the heat.

Assembly: Now it’s time to assemble the lasagna. In a greased baking dish, spread a thin layer of the Alfredo sauce on the bottom. Arrange a layer of lasagna noodles on top, followed by a portion of the chicken and mushroom mixture. Repeat this layering process until you’ve used up all the ingredients, finishing with a layer of Alfredo sauce on top.

Baking: Cover the baking dish with aluminum foil and place it in the preheated oven. Bake for 25-30 minutes, or until the lasagna is heated through and the edges are bubbly. Remove the foil during the last 10 minutes of baking to allow the top to lightly brown.

Serving: Once the lasagna is done baking, remove it from the oven and let it cool for a few minutes before serving. Garnish with freshly chopped parsley for a pop of color and added freshness, if desired. Slice into generous portions and serve alongside a crisp green salad or garlic bread for a complete meal.