In a deep frying pan, heat the curry paste and coconut cream together over a low heat, stirring. Pour in the milk, stir well, and bring to a simmer.
Add the spring onions and butternut squash and cook for about 10 minutes, until the squash is just tender. Add the rest of the vegetables and simmer for another 5 minutes.
Season with fish sauce to taste, sprinkle over the coriander and serve on noodles or rice, with the lime wedges on the side.