Soak the dried porcini mushrooms in white wine until soft. Score the fat on the duck breast, season with salt and pepper and start cooking in a hot pan skin side down without adding any fats to the pan. Allow to cook for 3 minutes, turn and cook for further 3 minutes. Remove from heat and allow resting. Drain excess fat from the pan, fry the onion, garlic and mushrooms in the same fat, pour in the soaked dried mushrooms together with the obtained liquid. Add the sage and the tomatoes; crush slightly and simmer for 10 minutes. Slice the duck breast and add to the sauce simmer for further 2 minutes. Serve tossed with the cooked pasta, sprinkled pine nuts, sage leaves and a drizzle of truffle oil.