Prep the Noodles: Boil lasagna noodles in salted water until al dente. Drain and set aside. Lay them flat on parchment paper to prevent sticking.

Sauté the Mushrooms: In a large skillet, heat olive oil over medium heat. Add the onions and cook until translucent, about 4-5 minutes. Add the garlic and cook for an additional minute. Toss in the sliced mushrooms and cook until they release their moisture and become golden brown, about 8-10 minutes. Season with salt, pepper, and dried herbs. If using spinach, add it now and cook until wilted.

Prepare the Cottage Cheese Mixture: In a large mixing bowl, combine cottage cheese, half of the shredded mozzarella, and half of the grated Parmesan. Stir well and season with salt and pepper to taste.

Assemble the Lasagna: Preheat your oven to 375°F (190°C). Spread a thin layer of marinara sauce at the bottom of a 9x13-inch baking dish. Layer 3 lasagna noodles over the sauce. Top the noodles with half of the sautéed mushrooms, followed by a layer of the cottage cheese mixture. Repeat with another layer of sauce, noodles, mushrooms, and cottage cheese.

Final Layer: For the top layer, spread the remaining marinara sauce over the final set of noodles. Sprinkle the remaining mozzarella and Parmesan over the sauce.

Bake the Lasagna: Cover the dish with aluminum foil and bake for 30 minutes. Remove the foil and bake for an additional 10-15 minutes, until the cheese is bubbly and golden brown. Let the lasagna rest for 10 minutes before slicing and serving.