1. Preheat the oven to 375°F (190°C) and grease a baking dish.
2. Cook the lasagna noodles according to package instructions if using traditional noodles.
3. In a large skillet, heat olive oil over medium heat and sauté minced garlic until fragrant.
4. Add fresh spinach to the skillet and cook until wilted, then remove from heat and let cool slightly.
5. In a mixing bowl, combine ricotta cheese, sautéed spinach, one beaten egg, salt, pepper, and half of the grated Parmesan cheese.
6. Spread a thin layer of marinara sauce on the bottom of the prepared baking dish.
7. Place a layer of lasagna noodles over the sauce.
8. Spread a portion of the spinach-cheese mixture evenly over the noodles.
9. Sprinkle a layer of shredded mozzarella cheese on top.
10. Add another layer of marinara sauce over the cheese.
11. Repeat the layering process until all ingredients are used, finishing with marinara sauce on top.
12. Sprinkle the remaining mozzarella and Parmesan cheese over the final layer.
13. Cover the baking dish with aluminum foil and bake for 45 minutes.
14. Remove the foil and bake uncovered for an additional 15-20 minutes until the top is golden and bubbly.
15. Allow the lasagna to rest for 10-15 minutes before slicing and serving.