Heat a skillet to medium heat and spray with oil. Season zucchini strips with salt and pepper. Cook for 8 to 10 minutes. (The cooking time will vary according to how thinly you slice your zucchini.) Remove from heat and set aside.
Spray the pan again and add the spinach. Cook until the spinach wilts. Transfer to a plate lined with a clean towel and squeeze out excess moisture.
Preheat an oven to 350 degrees.
In a medium bowl, combine ricotta cheese, Parmesan, egg, garlic, basil, parsley and crushed red pepper. Stir in spinach and season with salt and pepper.
Coat a 13 x 9 casserole dish with cooking spray and spread ½ cup of the Marinara on the bottom.
Top with a layer of noodles, a layer of zucchini, ½ of the ricotta mixture and mozzarella.
Spread ⅓ of the remaining marinara and repeat the layers.
End with a layer of noodles, marinara and remaining mozzarella cheese. Bake for 30 minutes. Allow to cool for 15 minutes prior to serving.