A dear friend of mine shared this recipe many years ago and it's one that we enjoy often in my home. It's simple to prepare and has great flavor. It's one of those soups that is even better the next day. I'm not sure that my kids love it as much as I do but that's okay, more for me ;)
Heat the oi lin a large soup pot over medium heat.
Add the onion, garlic, and ginger and cook, stirring frequently, until softened, 6 to 8 minutes. Don't brown the mixture, reduce your heat if necessary.
Add the squash, carrots, broth, fish sauce, sugar, and curry paste.
Bring to a boil, then lower the heat and simmer, covered, until the vegetables are tender, about 20 minutes.
Using a hand-held immersion blender, pureé the soup until silky smooth.
(Alternatively, cool the soup slightly, then pureé in a blender in batches, making sure to leave the hole in the lid open to allow the steam to escape.
Next stir in the coconut milk, lime juice, and salt.
Bring everything to a simmer, then taste and adjust the seasonings.
Serve soup into bowls and drizzle with Sriracha and garnish with the scallions and cilantro.