Place the heritage potatoes in a saucepan and cover with cold, salted water.
Bring to a simmer and cook until just tender—test by piercing with a knife. Be careful, as they can overcook quickly.
As soon as the potatoes are cooked, drain them immediately and run them under cold water to stop the cooking process and help them cool down.
While the potatoes cool, prepare the dressing.
In a large bowl, whisk together the mayonnaise and white truffle oil.
Stir in most of the finely chopped spring onions, reserving a small amount for garnish.
Season the dressing generously with sea salt and freshly ground black pepper to compensate for the plain potatoes.
Once the potatoes are completely cold, slice them into uniform, bite-sized pieces.
Gently fold the cooled potato slices into the truffle mayonnaise until they are evenly coated.
Garnish with the reserved spring onions before serving.
