Preheat the oven to 375°F (190°C).
Cook the lasagna noodles according to package instructions.
Heat olive oil in a skillet over medium heat, add garlic and mushrooms.
Add spinach to the skillet and cook until wilted.
Combine the ricotta, heavy cream, salt, and pepper in a bowl.
Layer the lasagna: begin with noodles, then filling, mushrooms, spinach, ricotta mixture, and mozzarella.
Repeat layers until all ingredients are used, finishing with mozzarella and Parmesan on top.
Cover with foil and bake for 25 minutes, then remove the foil and bake for another 15 minutes.
Let it cool for about 10 minutes before slicing.