Bring a large pot of salted water to a boil. Cook the jumbo pasta shells according to package instructions until al dente. Drain and carefully rinse under cold water to stop the cooking process and prevent sticking. Set aside to cool.
In a large skillet, heat the olive oil over medium heat. Add the minced garlic and sauté for about 1 minute until fragrant. Add the shrimp, sprinkle with salt, pepper, and Italian seasoning, and cook until shrimp turn pink and opaque, about 3-4 minutes. Remove from heat and let cool slightly before chopping into smaller pieces.
In a mixing bowl, combine the ricotta cheese, half of the shredded mozzarella, grated Parmesan, chopped shrimp, and a few spoonfuls of Alfredo sauce. Mix gently until everything is evenly incorporated. Adjust seasoning with salt and pepper as needed.
Preheat your oven to 375°F (190°C). Pour a thin layer of Alfredo sauce in the bottom of your baking dish to prevent sticking. Carefully spoon the shrimp and cheese mixture into each shell, filling them generously. Place the stuffed shells in the baking dish, open side up, in a single layer.
Pour the remaining Alfredo sauce evenly over the stuffed shells. Sprinkle the remaining mozzarella cheese on top for a golden, bubbly finish. Cover the dish with foil and bake for 25 minutes. Remove the foil and bake for an additional 10 minutes or until the cheese is melted and slightly browned.
Remove the baking dish from the oven and let it rest for 5 minutes. Sprinkle freshly chopped parsley on top for a burst of color and freshness. Serve warm and enjoy!