Cook the noodles in a saucepan of boiling water for about 5 minutes, or until just tender.
Meanwhile, heat the oil in a saucepan. Add the spring onions and garlic and sauté gently for 1 minute.
Add the red chilli, fresh ginger, black bean sauce and vegetable stock and bring to the boil. Stir in the pak choi or spring greens, soy sauce, caster sugar and peanuts; reduce the heat and simmer gently, uncovered, for 4 minutes.
Drain the noodles and pile into serving bowls. Ladle the soup over the noodles and serve immediately.