Mix the turmeric with the ginger, sugar and fish sauce in a shallow dish to make a quick marinade. Toss the fish in the marinade and set aside for 5–10 minutes while you prepare the noodles.
Soak the noodles in boiling water for 10 minutes.
Meanwhile, heat the oil in a wok or frying pan and fry the fish over a high heat for 3–4 minutes until just cooked. Turn the fish carefully so it doesn’t break. Remove from the heat and add the chilli, herbs and spring onion and lightly toss together.
Drain the noodles and divide between four bowls. Add the chilli-herb fish pieces, scatter with the peanuts and serve.
