Heat the paste in a large saucepan and fry the squash for a few mins until well coated in the paste. Pour in the coconut milk and stock, and simmer for 10 mins. The squash should still have a bite to it. Add the drained noodles and beansprouts.
To freeze, turn off the heat immediately and leave to cool, then transfer to a suitable container for freezing. If you’re making this to eat now, add the salmon and prawns, and cook for 4-5 mins until the fish is cooked through.
If frozen, defrost overnight in the fridge, then return to a large saucepan. Add the salmon and prawns, cover, bring to the boil and simmer until the fish is cooked – it should only take 1-2 mins. Stir through the spring onions, then sprinkle with coriander and serve with some lime wedges.