1. Cook the jumbo shells in salted boiling water just until al dente. Drain and lay flat on a towel to prevent sticking.

2. In a skillet, heat olive oil and sauté garlic for 30 seconds. Add spinach and cook until wilted. Set aside to cool.

3. In a large bowl, mix ricotta, egg, Parmesan, salt, pepper, and the cooled spinach mixture until well combined.

4. Spread 1 cup of marinara sauce in the bottom of a 9×13-inch baking dish. Fill each shell with the cheese mixture and place into the dish.

5. Top with remaining marinara and sprinkle mozzarella evenly over the shells.

6. Cover with foil and bake at 375°F for 25 minutes. Remove foil and bake an additional 10 minutes until bubbly and golden.

7. Let rest for 5 minutes before serving. Garnish with fresh basil if desired.