In a large skillet, on medium heat, melt the butter. Add the pumpkin, sage, salt, and pepper, and cook on medium heat until the pumpkin is tender, about five minutes. Set aside.
While the pumpkin cooks, cook the Fettuccini: Bring a big pot of water to a boil. Add three tablespoons of kosher salt and cook the pasta until al dente, according to the package directions. Drain and set aside.
While the water comes to a boil, and the pasta cooks, make the Carbonara sauce: In a large skillet on low heat, heat up the oil. Add the pancetta and cook it until it's crisp, add the red pepper flakes and garlic and cook another minute. Pour in the wine and stir to deglaze the pan. Simmer until ¾ of the wine has evaporated. Stir in the cream and bring it to a simmer. Remove the skillet from the heat.
In a double boiler, over simmering water, whisk together the egg yolks and cheese, just until it thickens, for about a minute. Take care to not scramble the eggs.
Add the drained pasta to the skillet along with the egg and cheese mixture. Stir and toss quickly until everything is combined. Stir in the pumpkin. Serve with shaved parmesan.