Rinse the leek under running water and cut into fine rings. Remove the skin of the salsiccia (or any other well-seasoned raw, coarse sausage), cut the sausage meat into bite-sized pieces and then heat the oil in a pan over a high temperature. When the oil is hot, add the salsiccia and sauté for a few minutes until it takes on a color all around.
Add the leek and cook for 3 minutes. Deglaze with white wine and continue to simmer until almost half of the liquid has evaporated. Season with salt and pepper and remove from the stove. In the meantime, cook the pasta in plenty of salted water and drain after the cooking time indicated on the package. Mix the pasta with the prepared sauce and butter and stir well. Sprinkle with the grated Parmigiano cheese and garnish with parsley before serving.