Melt 2 tbsp beef dripping in a large pot (you can skip this and the next step if not using onion - See Notes)
Peel and finely chop 1 onion - soften in beef dripping for 5-10 minutes until they start to turn golden
Peel and chop 750 g turnip/swede/rutabaga and 1 kg potatoes into chunks - See Notes
Remove beef dripping and onion from the pot into a separate ramekin (this will be added back in later)
Add chopped potatoes into large pot with a generous helping of salt and white pepper and fill with cold water
Bring to the boil (5 minutes), and cook until knife tender (approx. 20 minutes - but this will vary dependant on how big you’ve chopped your vegetables)
Drain the vegetables and add 80 g salted butter and mash until combined
Stir through cooked onions and beef dripping then season with salt and white pepper to taste
Garnish with extra butter and 6 tbsp chives freshly chopped to serve
