Begin by preheating your oven to 375°F (190°C).
Cook the lasagna noodles according to the package instructions until they reach an al dente texture. Drain them well and set aside on a clean surface or lightly greased parchment paper to prevent sticking.
In a large skillet over medium heat, pour in the extra virgin olive oil. Once hot, add the minced garlic and sauté for about 1 minute until it becomes fragrant but not browned.
Introduce the sliced mushrooms to the skillet, stirring frequently. Cook for 5-7 minutes until they are tender and have released their juices, becoming slightly golden.
Add the chopped spinach to the mushroom mixture along with the dried oregano, dried basil, and a generous pinch of salt and black pepper. If you enjoy a bit of spice, include the red pepper flakes. Sauté for an additional 2-3 minutes until the spinach has wilted. Remove from heat and set the mixture aside.
In a separate mixing bowl, blend together the ricotta cheese, half of the grated Parmesan, a pinch of salt, and freshly cracked black pepper, stirring until the mixture is smooth and creamy.
To assemble the lasagna, spread a thin layer of marinara sauce on the bottom of a 9x13 inch baking dish to prevent sticking.
Place 3 lasagna noodles over the sauce. Spread half of the ricotta mixture over these noodles, then layer on half of the spinach and mushroom mixture, followed by a sprinkle of shredded mozzarella cheese.
Repeat the layering process: add a new layer of marinara sauce, another 3 noodles, the remaining ricotta, the rest of the spinach and mushroom mix, and another sprinkle of mozzarella.
For the final layer, add the last three noodles on top. Cover with the remaining marinara sauce, sprinkle the rest of the mozzarella cheese, and finish with the leftover grated Parmesan cheese.
Cover the baking dish tightly with aluminum foil, ensuring it doesn't touch the cheese. Bake in the preheated oven for 25 minutes.
After 25 minutes, carefully remove the foil and return the dish to the oven for an additional 15 minutes, or until the cheese topping is golden and bubbly.
Remove the lasagna from the oven and allow it to set for 10 minutes before slicing. This resting time helps with easier servings.