Preheat the oven to 320 F. Remove the package from the frozen duck, transfer it to a baking dish. Cover the baking dish with foil and place in the oven for 2 hours.
After 2 hours, carefully remove the foil and rub the duck on all sides with olive oil, and then with a mixture of spices and salt. Place rosemary sprigs in baking dish and recover. Bake for 1 more hour at 380 F.
After that time, remove the foil and continue roasting the duck at 400 degrees F for about 20-30 minutes until you acquire a golden crisp on top and fully cooked inside - the temperature inside the breast should be about 140 F.
Remove from the oven and allow to rest for 15 minutes covered, then serve whole or cut into pieces.