Step 1: Prepare the Noodles

Preheat oven to 375°F (190°C).

Cook lasagna noodles in salted boiling water until al dente. Drain and set aside.

Step 2: Make the Mushroom & Spinach Filling

Heat olive oil in a large skillet over medium heat.

Add onion and sauté for 3-4 minutes until soft.

Stir in garlic and cook for 30 seconds.

Add mushrooms, thyme, salt, and pepper. Cook until mushrooms soften and release their liquid.

Add spinach and cook until wilted, about 2 minutes. Remove from heat.

Step 3: Assemble the Lasagna

Layer 1: Spread a thin layer of marinara sauce at the bottom of a 9×13-inch baking dish.

Layer 2: Place 3 lasagna noodles on top.

Layer 3: Spread half of the ricotta, followed by half of the mushroom mixture.

Layer 4: Sprinkle ⅓ of the mozzarella and Parmesan cheeses.

Repeat: Add another layer of noodles, ricotta, mushrooms, and cheese.

Final Layer: Top with the last 3 noodles and spread the remaining marinara sauce over them.

Step 4: Bake the Lasagna

Cover with foil and bake for 25 minutes.

Remove foil and bake 10-15 minutes more until cheese is golden and bubbly.

Let it cool for 5-10 minutes, then garnish with fresh basil and serve!