1. Preheat your oven to 375°F (190°C).
2. Cook the jumbo pasta shells according to package instructions until al dente. Drain and set aside.
3. In a large mixing bowl, combine the shredded chicken, ricotta cheese, mozzarella cheese, Parmesan cheese, beaten egg, minced garlic, Italian seasoning, salt, and pepper. Mix until well combined.
4. Pour half of the marinara sauce into the bottom of a 9×13 inch baking dish, spreading it evenly.
5. Fill each shell with the chicken and cheese mixture using a spoon or your hands, then place them in the baking dish over the marinara sauce.
6. In a separate saucepan, heat the olive oil over medium heat. Add the heavy cream and remaining marinara sauce, stirring until well combined. Pour this creamy sauce over the stuffed shells in the baking dish.
7. Cover the dish with aluminum foil and bake in the preheated oven for 30 minutes.
8. Remove the foil and bake for an additional 10-15 minutes, until the cheese is bubbly and golden brown.
9. Once baked to perfection, let the dish sit for a few minutes before serving. Garnish with fresh basil if desired.

Growing up, my mom always taught me the importance of letting flavors meld and rest, so don’t skip the resting period before serving. It makes all the difference!