Preheat oven to 375°F (190°C).
Spread a thin layer of marinara sauce at the bottom of a baking dish.
Layer 3 lasagna noodles over the sauce.
Spread a layer of vegan ricotta cheese over the noodles.
Add a layer of spinach, mushrooms, and zucchini.
Repeat layers until all ingredients are used, ending with a layer of marinara sauce.
Top with shredded vegan mozzarella cheese.
Cover with foil and bake for 30 minutes.
Remove foil and bake for an additional 10 minutes, or until the cheese is melted and bubbly.
Let it cool for 10 minutes before serving.