Bring water to a boil and cook the pasta according to the package directions. When the pasta is done, reserve some pasta water before draining it. Return the pasta to the pot. While the pasta cooks, make the sauce.
Make the sauce:
Inside your blender jar, place the milk, Greek yogurt, Parmesan cheese, cornstarch, salt, pepper, garlic powder, and Italian seasoning. Blend until smooth, stopping the blender to scrape down the sides if necessary. Blending the ingredients keeps the sauce from separating.
Pour the sauce into a saucepan, and heat it over medium heat, stirring frequently, until it begins to simmer. Reduce the heat to low and cook it for 5 minutes.
Pour it over the pasta and use tongs to coat the pasta with the sauce. Slowly add some of the reserved pasta water, about ¼ cup, and combine until you have a sauce consistency you like.
Serve:
Serve the creamy pasta topped with additional Parmesan cheese.