Preheat oven to 350°F
Place zucchini on parchment paper and lightly salt. Let sit for ten minutes. Then pat dry and heat in 350 degree oven for about 10 minutes.
In a large bowl, mix the fresh ricotta, 1/3 of the Parmesan, spinach, and mushroom mixture. Season with oregano, Italian seasoning, salt and pepper.
To assemble the lasagna: Pour enough marinara sauce to coat the bottom of a 9x13 baking dish. Layer 1/3 of the zucchini noodles like you would lasagna. Add 1/3 of the ricotta mixture and spread smoothly to cover zucchini. Put small dabs of mozzarella on top and a few basil leaves. Sprinkle Parmesan on top. Repeat until you have three layers. Make sure the top is mainly cheese.
Bake about 45-50 minutes until top is nicely browned.
Let rest for about 10 minutes.