In a 6 to 8 quart heavy bottomed casserole or Dutch Oven, heat olive oil over high heat until it is just smoking.
Season duck chunks with salt and pepper, and sear pieces on all sides until browned.
Remove the browned meat to a plate and set aside.
2. To the same pot, add onion, carrot, celery and garlic.
Cook until lightly browned, stirring constantly with a wooden spoon.
Add all the mushrooms and repeat process, and then add the tomato paste.
Stir thoroughly and cook until a rusty red brown color appears on bottom of pan, about 5 to 6 minutes.
Add red wine, chicken stock and rosemary, then bring mixture to a boil.
Return the browned duck meat to the pot, submerging it in liquid and bring to a boil.
Reduce heat to a simmer and cook, uncovered, until meat is tender, soft, almost falling apart; approximately 1 1/2 hours.
It is very important not to boil.
3. After meat is done, skim the fat from the surface of the sauce with a small ladle.
Continue to cook sauce over low heat until the consistency is thick and chunky.
Adjust the seasoning.
4. Bring 6 quarts of water to a boil and add 2 tablespoons salt.
Add pappardelle noodles, and drain when they float to the surface; do not wash.
5. Add noodles to a large sauté pan and ladle ragu over noodles.
Toss gently together to coat noodles with ragu.
Divide among six bowls, grate parmesan over each bowl, and serve immediately.