Heat oil in a Dutch oven set over medium-high heat.
Add onions and cook for 2 minutes.
Stir in garlic and cook for 20 seconds.
Stir in curry paste and ginger; continue to cook for 30 seconds, or until fragrant.
Add squash and generously season with salt and pepper.
Add coconut milk and vegetable broth; bring to a boil.
Reduce heat to medium and continue to cook for 10 to 15 minutes, or until squash is very tender.
Stir in lime juice and taste the soup for salt and pepper; adjust as needed.
Using an immersion blender, blend the soup until smooth. You can also blend it in a blender in batches.
Taste for seasonings and adjust accordingly.
Ladle soup into bowls.
Garnish with yogurt, cilantro, pumpkin seeds, and/or sriracha sauce.