In a large bowl, remove the casings from the sausages and crumble the meat. Discard the casings and bring a large pot of water to a boil for the pasta.
In a large frying pan or skillet, heat olive oil over medium heat. Add the chopped onion and cook until softened. Add the crumbled sausage to the pan. Cook until browned, breaking any large pieces with a spatula.
Add white wine, stirring constantly, and cook until the wine has mostly evaporated, about 2 minutes.
Lower the heat, cover, and simmer the sausage for 10 minutes in its juices. Season with salt and pepper.
Uncover, add fresh cream and truffle shavings (if using), along with half of the grated pecorino cheese. Simmer for 3-4 minutes until the sauce thickens slightly, then remove from heat.
Meanwhile, salt the pasta water and bring it to the boil again. Then, cook the pasta al dente according to the package instructions. Reserve some cooking water before draining.
Add the drained pasta to the sausage sauce, mixing over low heat. If needed, adjust the consistency with reserved pasta water.
Plate the pasta, topped with the remaining pecorino, fresh black pepper, and more truffle shavings if desired.