Step 1: Preheat and Prep
Preheat your oven to 375°F (190°C). Grease a 9×13-inch baking dish to prevent sticking.
Step 2: Prepare the White Sauce
- In a medium saucepan, melt the butter over medium heat.
- Add the flour and whisk continuously for about 1 minute to form a smooth paste.
- Gradually add the milk, whisking constantly to avoid lumps. Continue to cook until the sauce thickens, about 5-7 minutes.
- Once thickened, add garlic powder, nutmeg, salt, and pepper. Stir well and remove from heat.
Tip: If you prefer a richer sauce, you can substitute some of the milk with heavy cream.
Step 3: Cook the Mushrooms and Spinach
- In a large skillet, sauté the mushrooms in a little butter over medium heat for 5-7 minutes until softened.
- Add the spinach and cook for an additional 2 minutes, or until wilted. Season with salt and pepper.
Step 4: Mix the Filling
In a large bowl, combine the shredded chicken, ricotta cheese, mozzarella, Parmesan, Italian seasoning, and the cooked mushroom-spinach mixture. Stir until everything is well combined.
Step 5: Assemble the Lasagna
- Spread a thin layer of the white sauce on the bottom of the prepared baking dish.
- Lay 4 lasagna noodles over the sauce.
- Spread a third of the chicken, mushroom, and spinach mixture over the noodles, followed by a third of the white sauce.
- Repeat the layering process two more times, finishing with a final layer of noodles and white sauce on top.
Step 6: Bake
- Cover the lasagna with aluminum foil and bake for 25 minutes.
- After 25 minutes, remove the foil and bake for an additional 10-15 minutes, or until the top is golden and bubbly.
Step 7: Rest and Serve
Allow the lasagna to rest for 10 minutes before slicing and serving. This helps the layers set and makes it easier to cut into neat squares.