Creating the beautiful layers in your Mushroom and Spinach Lasagna is a rewarding process. Follow these steps to master this incredible dish:

1. Preheat the Oven: Preheat your oven to 375°F (190°C).

2. Cook the Noodles: In a large pot of boiling salted water, cook the lasagna noodles according to the package instructions. Drain and set aside.

3. Sauté the Vegetables: In a large skillet, heat olive oil over medium heat. Add chopped onions and minced garlic, cooking until soft and fragrant.

4. Add Mushrooms and Spinach: Add sliced mushrooms to the skillet and sauté until they release their moisture, about 5 minutes. Then, add in the chopped spinach and cook until wilted. Season with salt and pepper. Remove from heat.

5. Prepare Cheese Mixture: In a mixing bowl, combine ricotta cheese, egg, half of the mozzarella cheese, and half of the Parmesan cheese. Mix well and season with salt and pepper.

6. Assemble the Lasagna:
– Spread a thin layer of marinara sauce on the bottom of a 9×13-inch baking dish.
– Layer 3 cooked noodles over the sauce.
– Spread half of the ricotta cheese mixture over the noodles.
– Add half of the sautéed mushroom and spinach mixture over the ricotta.
– Repeat the layering: marinara sauce, noodles, ricotta, vegetables, and finish with a final layer of noodles and remaining marinara sauce.

7. Top with Cheese: Sprinkle the remaining mozzarella and Parmesan cheese evenly over the top.

8. Bake: Cover the dish with foil (to prevent sticking) and bake in the preheated oven for 30 minutes. Remove the foil and bake for an additional 15 minutes or until the cheese is bubbly and golden brown.

9. Cool Down: Once baked, let the lasagna cool for about 10 minutes. This will make it easier to slice.

10. Serve: Cut into squares and serve warm. Garnish with fresh basil leaves if desired for an added touch.