Cook the noodles or spaghetti in boiling, salted water until they are just tender. Drain, set aside and keep hot.

Heat the oil in a large frying-pan. Add the onion, ginger and pork and fry for 2 minutes, stirring constantly. Stir in the butter until it melts. Add the vegetables and shrimps or prawns and fry for 1 1/2 minutes, stirring constantly. Stir in the soy sauce and sugar and stir-fry for a further 1 1/2 minutes. Remove the frying-pan from the heat, set it aside and keep hot.

Pour the water into a saucepan and bring to the boil. Crumble in the stock cube and stir to dissolve it. Add half the pork mixture and the stock and bring the mixture to the boil. Stir in the noodles or spaghetti and simmer for 3 minutes.

Meanwhile, return the frying-pan to high heat and stir-fry the remaining pork mixture for 1 minute to reheat it.

Divide the noodle or spaghetti mixture between four or six individual bowls. Spoon over the remaining pork mixture and serve at once.