Preheat the oven: Preheat your oven to 350°F (175°C). Spray your baking dish with olive oil spray to prevent sticking.
Prepare the vegetables: If using fresh spinach, sauté it lightly in a non-stick pan until wilted. If using frozen spinach, thaw and drain excess water. If adding zucchini, shred it and squeeze out excess moisture.
Mix the ingredients: In a large bowl, combine ricotta cheese, egg, cooked spinach, lean ground turkey or chicken, shredded zucchini (if using), Parmesan cheese, garlic powder, dried basil, salt, and pepper. Stir everything until well combined.
Transfer to the baking dish: Spoon the ricotta mixture into the prepared baking dish and spread it evenly.
Bake: Place the baking dish in the oven and bake for 25-30 minutes or until the top is golden and the dish is set.
Serve: Once done, remove from the oven and let it cool for a few minutes before slicing into portions. Serve warm.