Steam the potatoes till very soft. Meanwhile melt the butter in a pan and cook the onions and apples over low heat till soft. Mash the potatoes without butter or milk. Add the onion and apple mix, parsley and seasoning and mix well.  Cool completely.
Traditionally in Ireland the cavity of the goose is stuffed with this mix. Wipe the bird inside and out with kitchen paper. Place the cold stuffing into the cavity. Weigh the stuffed bird to calculate cooking time.( Makes enough to stuff a 4.5kg bird)