First, fill a medium pan with water and bring to the boil. In a medium bowl, stir together the vinegar, sugar and fish sauce until the sugar is mostly dissolved. Slice the cavolo nero lengthwise into ribbons 1cm wide (discard the tough inner core) then, using your hands, scrunch into the vinegar mix. Set aside to lightly pickle.
Carefully add the eggs to the pan of boiling water. Simmer on medium for six minutes then remove with a slotted spoon and plunge into a bowl of cold water to stop them cooking any further. (If you gently crack the base of the eggs just before you add to the cold water, they will be easier to peel.)
Next, add the noodles to the pan of water and cook over a high heat for the time stated on the packet (around five minutes). Refresh under cold water, drain thoroughly and place in a large mixing bowl.
Toast the sesame seeds in a small frying pan over a high heat for one to two minutes until golden and you can smell the natural oils being released. Transfer to a plate to cool.
Top, tail and peel the carrots then, using a speed peeler, shave ribbon lengths.
To assemble add the carrots, spring onions and ginger to the noodles along with the sesame oil and pickled cabbage (including one tablespoon of the pickling juice).
Divide between four bowls. Peel the eggs then halve lengthwise and place on top of the noodles. Splash each egg yolk with some of the pickling juice, and scatter over the remaining sesame seeds and chilli flakes, if using.