1. Heat the noodles according to pack instructions and set aside. Meanwhile, toss the chicken with 1 tbsp soy sauce and 1 tsp cumin and let it sit for a minute or two. For the sauce, mix the remaining 1 tbsp soy sauce and 1 tsp cumin with the peanut butter and chilli flakes. Loosen with 5 tbsp just-boiled water.
2. Heat 1⁄2 tbsp oil in a frying pan or wok, then fry the chicken over a high heat for 3-4 minutes, until golden and just cooked through. Scoop onto a plate and set aside.
3. Keeping the heat high, add the remaining 1⁄2 tbsp oil, then fry the onion for 1 minute. Add the ginger and garlic to the pan, sizzle briefly, then tip in the cavolo nero, noodles and chicken. Turn everything over a few times in the pan using tongs. The cabbage should retain plenty of texture. Pour in the sauce, shake the pan a little, and serve immediately.