Bring a large pot of water (at least 4 qts) to boil. Cook chosen pasta 1 minute less than the package directions suggest. You want it a little less than al dente.
Right before the pasta is finished cooking, heat a large skillet over low heat and add cream and butter. Bring to a low simmer until it thickens about 3-4 minutes. It should coat the back of a spoon. Turn off the heat.
Add the cheese and nutmeg along with the salt and pepper. Stir to incorporate.
Reserve ½ cup of pasta water and set aside. Drain the cooked pasta.
Using tongs, add the pasta to the sauce skillet and toss to coat with the sauce.
Add the pasta water as needed a little at a time to keep the sauce loose. Taste for seasoning.
Serve immediately and top with extra parmesan or fresh parsley.