Preheat your oven to 375°F (190°C).
In a large saucepan, heat olive oil over medium heat. Add minced garlic and sauté for about 1 minute until fragrant.
Add mushrooms, zucchini, and bell peppers to the saucepan. Cook for about 5-7 minutes until tender. Finally, stir in the spinach and cook until wilted. Season with salt, pepper, oregano, and basil.
In a mixing bowl, combine ricotta cheese, half of the grated Parmesan, and a pinch of salt and pepper. Mix until smooth.
In the baking dish, spread a thin layer of the cream sauce or a little milk on the bottom to prevent sticking.
Begin layering: Place three lasagna noodles over the sauce, then spread half of the ricotta mixture over the noodles.
Layer half of the sautéed vegetable mixture over the ricotta. Sprinkle with one-third of the mozzarella cheese.
Repeat the layering process: noodles, ricotta, vegetables, and more mozzarella until all ingredients are used, finishing with noodles and the remaining mozzarella and Parmesan on top.
Pour the remaining cream sauce over the top layer. Tightly cover with aluminum foil.
Bake in the preheated oven for 25 minutes, then remove the foil and bake for an additional 15 minutes until the cheese is bubbly and slightly golden.
Remove from the oven and let it rest for about 10 minutes before slicing and serving.