1. Warm a pan over medium heat, then lightly spray with oil. Lightly season the zucchini strips with salt and pepper. Cook for 8 to 10 minutes, or until tender. Cooking time will depend on how thinly you've sliced the zucchini. Remove from heat and set aside.
2. Lightly spray the pan again and add the spinach. Continue cooking until the spinach has wilted. Transfer the spinach to a towel-lined plate and gently squeeze out any excess moisture.
3. Preheat oven to 350 degrees Fahrenheit (175 degrees Celsius).
4. In a medium bowl, combine the ricotta cheese, Parmesan, egg, garlic, basil, parsley, and crushed red pepper. Mix in the spinach and season with salt and pepper.
5. Lightly coat a 13x9 casserole dish with cooking spray and spread 1/2 cup of the marinara sauce on the bottom.
6. Top with a lasagna noodle, a layer of the zucchini, 1/2 of the ricotta mixture, and half of the mozzarella.
7. Spread 2/3 of the remaining marinara sauce over the layers.
8. Repeat the layers. Finish with a layer of noodles, marinara, and the remaining mozzarella. Bake for 30 minutes. Let rest for 15 minutes before serving.