Heat the olive oil in a large soup pot over medium high heat. Add in the onion and saute for about 5 minutes.
Add in the ginger, curry paste, and salt and toast for 1 minute.
Add in the sweet potatoes, coconut milk, and vegetable broth. Bring to a boil, then reduce the heat to medium-low. Simmer until the sweet potatoes are tender, about 15 minutes.
Use an immersion blender
to puree the soup in the pot, or transfer in batches to a food processor or blender and return the pureed soup to the pot.