Add 1 tablespoon salt to a large pot of water and bring to a boil.
Meanwhile, in a large (12-inch) saute pan, heat the cream over medium heat until it comes to a simmer. Add the truffle butter, 1 teaspoon salt, and 1/2 teaspoon pepper, lower the heat to very low, and swirl the butter until it melts. Keep warm over very low heat.
Add the pasta to the boiling water and cook for 3 minutes, exactly. (If you're not using Cipriani pasta, follow the directions on the package.) When the pasta is cooked, reserve 1/2 cup of the cooking water, then drain the pasta. Add the drained pasta to the saute pan and toss it with the truffle-cream mixture. As the pasta absorbs the sauce, add as much of the reserved cooking water, as necessary, to keep the pasta very creamy.
Serve the pasta in shallow bowls and garnish each serving with a generous sprinkling of chives and shaved Parmesan. Sprinkle with salt and pepper and serve at once.
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