01 - Bring a large pot of salted water to a boil. Cook penne pasta for 10 to 12 minutes until al dente. Reserve 1/4 cup pasta water, drain pasta, and set aside.
02 - In a large skillet over medium heat, melt butter. Add minced garlic and cook for 30 seconds until aromatic.
03 - Lower heat to medium-low. Add heavy cream, milk, salt, black pepper, red pepper flakes if using, and Italian seasoning. Stir thoroughly and simmer for 2 to 3 minutes.
04 - Gradually add grated Parmesan cheese, stirring constantly to ensure even melting. If sauce thickens excessively, blend in reserved pasta water incrementally until desired consistency is reached.
05 - Add drained penne to the skillet. Toss well to fully coat pasta in the sauce. Cook for an additional 1 to 2 minutes to integrate flavors.
06 - Remove skillet from heat. Top with chopped parsley, additional Parmesan, and a dash of black pepper as desired. Serve immediately.