Wash the duck under cool water and pat dry with paper towel. Rub salt and pepper on the inside and outside of the duck. Place the duck with the breast down into a roasting tin and roast for 30 minutes.
Turn the duck over and cook for a further 90 minutes until it is golden brown and crispy. Baste the duck repeatedly with the stock whilst cooking.
Place the duck on a preheated plate and cover with aluminium foil.
Drain and finely puree the gooseberries.
Deglaze the stock with water and then pass through a fine sieve. Add to a pan with the gooseberry puree and boil briefly. If the sauce is very watery, cook it for a while. Season with salt, pepper, nutmeg and cardamom.