4 tbsp. butter, plus more for greasing baking dish
2 tbsp. extra-virgin olive oil
3 boneless, skinless chicken breasts
1 tsp. Italian seasoning
Freshly ground black pepper
2 garlic cloves, minced
4 tbsp. flour
1/2 c. finely grated Parmesan
12 oz. cooked penne pasta
1 c. shredded mozzarella
1/4 c. chopped parsley
1/4 cup of cream
Preheat oven to 350 degrees F. Butter a large casserole dish and set aside.
Heat olive oil in a large skillet over medium heat. Season both sides of chicken breasts with Italian seasoning, salt, and pepper to taste. Add to pan and cook until the chicken is cooked through, about 4 to 5 minutes per side. Remove chicken and wipe the skillet clean. Let the chicken rest for 5 minutes before slicing crosswise.
Return the skillet to the stove over medium heat. Add butter and garlic and sauté until butter is melted and garlic is fragrant, about 30 seconds. Whisk the flour into the butter and garlic and cook until the mixture is bubbling and golden, 1 minute more. Gradually pour in the cream, whisking constantly. Bring mixture to a simmer and stir in Parmesan. Let simmer until the sauce thickens, about 2 to 3 minutes. Season to taste with salt and pepper.
In a large bowl, combine cooked pasta, chicken, and alfredo sauce. Spread about half of the pasta mixture on the bottom of the casserole dish then sprinkle with half of the mozzarella. Add the remaining pasta mixture and top with more mozzarella. Bake until bubbly and beginning to brown on top, about 20 minutes. Garnish with parsley and serve immediately.