Saute Onion, Leeks, Celery And Carrots In Butter For 5 Minutes. Add Stock, Wine And Lentils. Bring To A Boil. Add Parsley, Thyme And Bay Leaf. Cover And Simmer For 30 Minutes. Cook Pasta As Directed. Remove Bay Leaf And Discard. Stir In Pasta, Prosciutto, Salt, Pepper And Vinegar. Sprinkle With Mint And Serve.