Preheat the oven to 200 degreees F. Line a sheet pan with parchment paper. Spray the parchment paper with vegetable oil spray. Place the quince and the pear in a simgle layer on the parchment paper and sprinkle the brown sugar on top. Bake in a preheated oven until caramelized, about 45 minutes.

Meanwhile, in a bowl, combine the ground chicken and pork with the loose sausage meat, Parmesan, bread crumbs, egg, 1/2 tablespoon of the salt, pepper and nutmeg. When the mixture is amalgamated, add the quince and pear, along with the dried cherries, grapes, and pomegranate seeds.

Turn the oven up to 375 degrees F. Spoon the stuffing loosely into the main cavity of the goose (if there's extra, you can cook it in a buttered ovenproof dish). Rub the butter all over the goose, then season it with 1 1/2 tablespoons of the salt. Tuck the wing tips under the goose, and tie the legs together. Pour the olive oil into a roasting pan and place the goose in it, breast side up. Roast in the top third of the preheated oven until the goose begins to turn brown, about 30 minutes. Reduce the temperature to 325 degrees, pour the white wine over the goose, and cover it loosely with foil. Continue roasting, adding the stock when the wine has evaporated, and basting every 20 minutes, for 2 hours, or until an instant-read thermometer placed in the thickest part of the thigh registers 180 degrees.

Transfer the goose to a carving board with channels to hold the juice, cover it again with foil, and let it rest for a good 20 minutes before carving.