Cook the potatoes in a large saucepan of boiling, salted water for 15-20 minutes until tender. Cook the parsnip and swede at the same time in a large saucepan of boiling, salted water for 15-20 minutes until soft. Drain both saucepans and allow the vegetables to steam for a few minutes.
Roughly mash the potato with the butter, crème fraîche and seasoning. Roughly mash the turnip and parsnip together with seasoning.
Microwave the haggis for 6 minutes on full power until piping hot. Cut open the haggis and spoon onto serving plates.
Re-heat the mashed potato and mashed parsnip and turnip if necessary and spoon next to the haggis.