Clean, wash and chop the Brussels sprouts. Peel off the shallots, dice finely and sweat lightly in butter with the Brussels sprouts. Deglaze with port wine, Noilly Prat and white wine. Top up with cream, crème fraîche and stock, bring to the boil and simmer for 5 minutes. Add the parmesan and truffle oil and puree the soup very finely with a hand blender.