Bring a pot of salted water to a boil. In a large saute pan, heat the duck fat. When the fat has melted, add the onions and saute for 2 to 3 minutes. Season with salt and pepper. Using a sharp knife, remove the corn from the cob. Add the corn to the sauteed onions and continue to cook for 2 minutes. Add the mushrooms and saute for 2 to 3 minutes. Season the mixture with salt and pepper. Add the duck and garlic. Continue to saute for 2 minutes. Stir in the cream and bring the liquid to a simmer. Simmer the sauce, over medium heat, until the cream coats the back of a spoon, about 4 to 6 minutes.
Meanwhile, cook the pasta in the boiling water until cooked al dente, about 6 minutes. Drain the pasta and turn into a mixing bowl. Toss the pasta with the cream mixture. Add the cheese, truffle oil and chives. Toss until all the ingredients are incorporated. Season the pasta with salt and pepper. Mound the pasta in the center of each plate, garnish with fresh truffle shavings, if desired, and serve.