Cook the jumbo pasta shells in a large pot of salted water according to package directions. Once cooked, drain and set aside.

In a skillet, heat the olive oil over medium heat. Add the chopped onion and red bell pepper, cooking until they are soft and translucent. Stir in the minced garlic and cook until fragrant, about 1 minute.

In a bowl, combine the shredded chicken with the sautéed vegetables. Add Cajun seasoning, paprika, salt, and black pepper. Stir until everything is well mixed and heated through. Let it cool slightly.

In a large mixing bowl, combine the chicken-vegetable mixture with ricotta, mozzarella, and Parmesan cheese. Mix until everything is creamy and combined.

In a saucepan, melt the butter over medium heat. Whisk in the flour for about one minute to form a roux. Gradually add milk and heavy cream while continuously whisking to avoid lumps. Season with Cajun spices, garlic powder, salt, and black pepper. Let it simmer until the sauce thickens.

In a baking dish, spread half of the creamy sauce. Stuff each shell with the chicken-cheese mixture and place them in the dish. Pour the remaining sauce over the stuffed shells and sprinkle extra mozzarella cheese on top.

Cover the dish with foil and bake in a preheated oven at 375°F (190°C) for 20 minutes. Remove the foil and bake for another 10 minutes or until the top is golden and bubbly.

Allow the dish to cool for a few minutes before serving. Garnish with freshly chopped parsley for an extra pop of color!