Preheat the oven to 375°F (190°C).
Cook the lasagna noodles according to package instructions until al dente. Drain and lay them flat on a clean kitchen towel to cool slightly.
In a mixing bowl, combine ricotta cheese, spinach, Parmesan cheese, egg, garlic powder, onion powder, salt, and pepper. Mix until well combined.
Take one lasagna noodle and spread about 2-3 tablespoons of the spinach mixture evenly over it. Carefully roll it up from one end to the other. Repeat this process for the remaining noodles.
Spread a thin layer of marinara sauce on the bottom of a baking dish. Place the rolled-up lasagna noodles seam-side down in the dish.
Pour the remaining marinara sauce over the top of the rolled noodles, then sprinkle with shredded mozzarella cheese.
Cover the baking dish with aluminum foil and bake for 20 minutes. Remove the foil and bake for an additional 10 minutes, or until the cheese is bubbly and golden.
Once cooked, allow the dish to cool for a few minutes before serving. Garnish with fresh parsley if desired.