1. Cook the jumbo pasta shells in salted boiling water until al dente. Drain and lay them flat on a baking sheet to cool.

2. In a large skillet, heat olive oil over medium heat. Add ground turkey and cook until browned, breaking it up with a spoon.

3. Stir in garlic and cook for 1 minute, then add spinach and cook until wilted. Remove from heat and let the mixture cool slightly.

4. In a large mixing bowl, combine the cooked turkey-spinach mixture with ricotta cheese, 1 cup mozzarella, ¼ cup Parmesan, egg, Italian herbs, salt, and pepper. Mix until well combined.

5. Preheat oven to 375°F. Spread 1 cup of marinara sauce over the bottom of a 9×13-inch baking dish.

6. Stuff each cooled shell with about 1 to 2 tablespoons of the filling and place them in the baking dish.

7. Pour the remaining marinara sauce over the stuffed shells and top with the remaining mozzarella and Parmesan.

8. Cover the dish with foil and bake for 25 minutes. Remove foil and bake uncovered for another 10 minutes, or until cheese is bubbly and golden.

9. Let rest for 5 minutes before serving.