Boil lasagna sheets for 10 minutes until soft but still firm. Drain and set aside.
Marinate sliced mushrooms in olive oil, salt, and pepper. Pan-grill them until golden and aromatic.
In your baking dish, start layering:A layer of lasagna sheets, grilled mushrooms, fresh spinach, and dollops of ricotta cheese, a generous spoonful of chopped tomatoes, sprinkle with salt, pepper, and a touch of cracked chili (if using)Repeat for two more layers.
Cover the dish with foil and bake at 180°C (356°F) for 40 minutes.
Remove from oven, uncover, and top with mozzarella cheese.Bake again for 5–8 minutes on fan grill mode until the cheese melts and turns golden brown.
Serve hot with a fresh leafy side salad or a drizzle of balsamic glaze.