Step 1: Bring a large pot of salted water to a boil. Add the shell pasta and cook until al dente according to package directions. Before draining, scoop out ½ cup of the starchy pasta water to use later if the sauce needs thinning. Drain and set the pasta aside.

Step 2: Pat the chicken dry with paper towels for better browning. Heat olive oil and butter in a large skillet over medium-high heat. Add the chicken pieces, then season with Cajun seasoning, garlic powder, onion powder, Italian seasoning, salt, and pepper.

Step 3: Sear the chicken until golden brown and fully cooked, about 5–6 minutes per side depending on thickness. The goal is juicy chicken with slightly crispy edges. Once cooked, transfer to a plate and cover to keep warm.

Step 4: In the same skillet, pour in the heavy cream and stir in the softened cream cheese. Use a whisk to help the cream cheese melt smoothly into the sauce.

Step 5: Stir in the Parmesan cheese and keep mixing until the sauce becomes thick, creamy, and glossy. If it gets too thick, splash in a little reserved pasta water.

Step 6: Add the cooked shells into the sauce and stir until each one is coated. Toss in half of the mozzarella cheese, mixing until it melts and creates strings of gooey cheese throughout the pasta.

Step 7: Return the cooked chicken to the skillet, or plate the pasta first and arrange the chicken alongside. Sprinkle the remaining mozzarella cheese over the top and let it melt slightly before serving.

Step 8: Garnish with parsley and serve hot.