Place the pasta, whole milk, mustard, garlic powder, and nutmeg in a medium saucepan and mix together.
Turn the heat on to medium-high and bring the sauce to a simmer. Once it begins to simmer, turn the heat down to low.
Allow the pasta to cook in the sauce for 6 minutes, stirring the pasta mixture approximately once a minute, allowing the pasta to soak up the sauce.
Once the sauce is almost all soaked up, add ¼ cup of water, stir, and allow to cook for another 1-2 minutes. The pasta should be al dente at this point but, if it isn’t add, another ¼ cup of water and continue to stir, again allowing the pasta to soak up the additional water.
Once the pasta is at your desired consistency, remove the pan, and add the shredded cheese. Stir until the cheese is melted into the sauce and completely coats the pasta.
Top with parsley if desired.