I'm slow roasting a whole duck, but I have the neck and gizzard and some excess skin. Any ideas for the extra parts? Can I make duck broth?
Don't even think about trying to make stock from gizzard and skin. Neck, yes,with aromatics like carrots and leeks. Skin makes great crackliings (save the fat), and gizzards you can use for gravy. But to your point, don't waste them.
I don't see why the gizzard and neck could n't be simmered for a few hours and turned into a broth. Along with a carrot, celery and onion, additionally a bay leaf and some thyme would not hurt. If you want to use the skin, I agree with Pierino, render the fat starting with a cold pan on medium low heat. Then after the fat has been rendered crank the heat and fry the skin!
Nothing to add that hasn't already been said - pierino and Mr_Vittles speak the truth. There's nothing in this world like duck fat, it adds incredible flavor to all sorts of things, and the crispy skin is impossibly delicious.
I often use gizzards and necks for stock. Hearts too, but NOT the liver. However, I do love gizzards and if you're ever making confit, confit the gizzard too!
I use Ina Garten's recipe for roast duck which has you simmer the duck in chicken stock before roasting. It makes excellent roast duck, but the stock is unbelievable. I adore it.
And don't forget the Ginger duck recipe from Cooking for Mr. Latte. Finally made it last week and it was great. Best part, tho, is the gingery stock, which makes fabulous rice!