Season duck legs with salt, refrigerate overnight, then drain and pat dry.
In a heavy pot over low-medium heat, colour the duck legs, skin-side down,
until golden brown and the fat has cooked off. Turn over and colour the other side.
Remove from pan and drain excess fat.
Add carrot, onion, celery, garlic and mushrooms and cook over medium heat until
starting to colour. Add bay leaf, zest and tomato passata.
Add wine, bring to the boil. Add duck legs and cover with stock.
Cover the pot and simmer slowly 1.5-2 hours, until the meat starts to fall from the bone.
(Do not overcook until meat falls apart!)
Remove duck legs and allow to cool, then remove meat from the bones and
break into small pieces, leaving the skin attached.
Remove zest and bay leaf. Place duck meat back into the pot and adjust seasoning
with salt and pepper.
Cook pappardelle according to instructions. While the pasta is cooking, place the
ragu on the heat in a large frypan. Add the cooked pasta and toss in the frypan
with 1/3 of the parmesan. If the sauce is too thick, ass a little of the pasta water
so the sauce just coats the pappardelle. Add parsley and toss once more.
Divide between 4 pasta plates and top with remaining parmesan. Serve immediately.