Bring a large pot of salted water to a boil. Add the lasagna noodles and cook according to package directions until al dente (usually 8-10 minutes). Drain and lay them flat on a sheet of parchment or a clean kitchen towel to prevent sticking.
Heat olive oil in a large skillet over medium heat. Add the sliced mushrooms and cook until they release their moisture and start to brown, about 5-7 minutes. Toss in the minced garlic, dried oregano, and basil, stirring for another minute until fragrant. Add the fresh spinach and cook until wilted, about 2 minutes. Season with salt and pepper to taste. Remove from heat and set aside.
In a medium saucepan, warm the heavy cream over medium heat. Once it begins to simmer, slowly whisk in the grated Parmesan cheese until melted and smooth. Season the sauce with salt and pepper. Remove from heat once the sauce thickens slightly, about 4-5 minutes.
In a bowl, combine the ricotta cheese with half of the shredded mozzarella. Add a pinch of salt and pepper, mixing until smooth and creamy.
Preheat your oven to 375°F (190°C). Spread a thin layer of Alfredo sauce on the bottom of the baking dish. Arrange 3 lasagna noodles over the sauce, slightly overlapping. Spread half of the ricotta mixture evenly over the noodles. Spoon half of the sautéed mushroom and spinach mixture over the ricotta. Drizzle with more Alfredo sauce. Sprinkle with a third of the remaining mozzarella cheese. Repeat the layers: noodles, ricotta, mushrooms and spinach, Alfredo sauce, and mozzarella. Finish with the last 3 noodles, the remaining Alfredo sauce, and top with the remaining mozzarella and Parmesan cheese.
Cover the baking dish with aluminum foil and bake for 25 minutes. Remove the foil and bake uncovered for an additional 15-20 minutes, or until the cheese is bubbly and golden brown. Let the lasagna rest for 10 minutes before slicing.
Sprinkle the chopped fresh parsley over the top for a fresh, vibrant finish. Serve warm and enjoy!