Bring the cream and half the butter to a simmer in a small saucepan. Add the salt and the nutmeg, and continue to simmer until the cream is reduced by about one third.
Bring 4 quarts salted water to a boil in a large pot. Drop in the pasta. Remember, fresh pasta is ready in 2 to 3 minutes.
Meanwhile, stir the grated cheese, then the salmon and the ⅓ c