Slowly sauté the carrot, parsnip and celeriac in the butter, cook for about 5 mins until soft but not brown.
Add the chestnuts, stock and Marsala is using and cook for 15 mins.
Grate in the fresh nutmeg
Allow to cool for a few mins then transfer to a blender and blitz until smooth. You may want to do this in batches
Return to the pan and check the seasoning
Serve warm, topped with a tsp of crème fraiche and a sprinkle of chopped parsley