Preheat the oven to 350°F (175°C).

Cook the penne pasta according to package instructions until al dente. Drain and set aside.

In a large saucepan, melt the butter over medium heat. Once melted, stir in the flour and whisk until smooth, cooking for about 1-2 minutes.

Gradually add the half and half to the butter-flour mixture, whisking constantly until thickened.

Stir in the minced garlic, garlic powder, Italian seasoning, parmesan cheese, and cooked chicken. Mix until well combined.

Combine the cooked penne pasta into the sauce and mix until evenly coated.

Transfer the pasta mixture into a greased baking dish. Top with mozzarella cheese.

Bake in the preheated oven for 25-30 minutes or until the cheese is bubbly and golden brown.

Remove from the oven, let cool slightly, and garnish with freshly ground black pepper and parsley before serving.