Put a pan of salted water on to boil. Peel and thinly slice the onion. Peel the carrot and use a vegetable peeler to shave ribbons off it. When you've peeled it down to a thin core, use a sharp knife to finely slice the carrot core. Halve, quarter or slice the shiitake mushrooms, depending on how big they are. Finely slice the cavolo nero, discarding any dry ends.
The water should be boiling by now. Drop 2 nests of noodles into the pan. Simmer for 3 mins till just cooked. Drain. Tip back into the pan. Add 2 tsp oil and toss to mix, using a fork to pick up and separate the noodles. Set aside.
Set a wok or deep frying pan over a high heat for 2 mins. Add ½ tbsp oil and the onion. Stir fry for 5 mins till the onion is golden.
Add the mushrooms, carrot and cavolo nero to the pan. Stir fry for 5 mins till the veg have softened.
While the veg cook, stir 1 tbsp Worcester sauce with the tamari and honey. Add the sauce mix to the pan. Tip in the drained noodles. Toss together with the veg over the heat for 2 mins to warm everything through.
Add the sesame seeds to the pan and toss a few times to work them through the noodles and veg. Divide the yakisoba between two warm bowls and serve.