1. Bring a large pot of salted water to a boil. Cook the jumbo pasta shells until just al dente. Drain and set aside.

2. In a skillet, heat olive oil over medium heat. Add grated zucchini and sauté until most moisture evaporates. Add garlic and cook for 1 minute. Let cool slightly.

3. In a large mixing bowl, combine ricotta, half of the mozzarella, 2 tablespoons Parmesan, sautéd zucchini, garlic, herbs, egg, salt, and pepper. Stir until well mixed.

4. Fill each pasta shell generously with the ricotta-zucchini mixture.

5. Spread half of the marinara sauce in a baking dish. Arrange the stuffed shells in the dish and top with remaining sauce.

6. Sprinkle remaining mozzarella and Parmesan over the top.

7. Cover with foil and bake at 375°F (190°C) for 25 minutes. Uncover and bake for 10 more minutes until golden and bubbly.

8. Serve hot, garnished with fresh herbs if desired.