Preheat oven to 170°C.
Wash and dry the potatoes leaving the skins on.
Place enough salt in the base of a small baking tin to just cover the base.
Brush the potatoes with EVOO and roll across the salt, preferably filing the tray with potatoes.
Bake for 1 hour approximately and then test for doneness. They shouldn’t be totally soft yet.
Increase oven temperature to 200°C and finish baking for a further 30 minutes.
Place onto a plate, removing excess salt from the bottoms of the potatoes. (You can keep the baked salt and use it at the table if desired.)
Split with a cross cut and serve with plenty of Truffle Butter and additional MRS Truffle Salt to taste.
To make the butter, place the parmesan into the Thermomix bowl and mill 10 sec/speed 10.
Add butter, truffle salt and half the spring onions and mix 6 sec/speed 6. Roll and wrap in baking paper until use. Slice off portions of butter to use on your hot potatoes with the remaining spring onions on top.