1. Skin and crumble the sausage, and cook with olive oil over high heat until brown.
2. Deglaze with wine and reduce well.
3. Add leeks, lower the heat and cook for five minutes.
4. Meanwhile, cook pasta according to package directions, but drain three minutes prior to the end time. Reserve some cooking liquid.
5. Add pasta to the sauce, add cooking water and toss over high heat until pasta is cooked and sauce thickens.
6. Remove from the heat and stir in butter, cheese and parsley before serving.