Step 1: Cook the Mushrooms and Tomatoes

• Heat olive oil in a large skillet over medium heat. Add the chopped onions and cook until translucent (3–4 minutes). Add the sliced mushrooms and cook for 8–10 minutes, stirring occasionally. Season with thyme, oregano, salt, and pepper. Add white wine (optional) and cook until evaporated (2-3 minutes). Add grape tomatoes and cook for another 2–3 minutes. Set aside.

Step 2: Make the Bechamel Sauce

• In a medium saucepan, melt butter over medium heat. Add flour and whisk for 2–3 minutes until light golden. Gradually add the warmed milk, whisking constantly. Season with nutmeg, salt, and pepper. Cook, whisking occasionally, until the sauce thickens. Set aside.

Step 3: Assemble the Lasagna

• Preheat the oven to 375°F (190°C). Cook lasagna noodles as per the package instructions. Spread a thin layer of bechamel sauce at the bottom of a 9×13-inch baking dish. Layer the lasagna noodles over the sauce. Add half of the mushroom and tomato mixture, half of the chopped spinach, and one-third of the bechamel sauce. Sprinkle one-third of the mozzarella and Parmesan cheese on top. Repeat the layers.

Step 4: Bake the Lasagna

• After the final layer of cheese, cover the lasagna with aluminum foil and bake for 25 minutes. Remove the foil and bake for an additional 20 minutes or until the top is golden and bubbly.

Step 5: Cool and Serve

• Remove the lasagna from the oven and let it cool for 5–10 minutes before slicing. Garnish with fresh basil leaves, if desired.