For the whisky cream sauce:
Melt the butter in a small saucepan then add the whisky.
Cook off the alcohol (2-3 minutes) then add the cream, stock and mustard and whisk over a medium heat until thickened then set aside.
Prick your haggis bung all over with a fork and wrap it tightly in two layers of foil.
Place in a pot of cold water and bring it to the boil then turn down the heat to a simmer for 90 minutes.
Put the potato and turnip in a pan of cold water, bring to the boil and cook for 30 minutes until mashable.
Drain well and return to the pot with 50g of butter. Mash until the potato and turnip are combined but not creamy, you want the veg to have a bit of texture and bite.
Reheat the whisky sauce, plate up the haggis with the clapshot and enjoy with a wee dram.