In a large saucepan or dutch oven, heat the olive oil over medium heat. Add the chopped onion and cook until softened, about 5 minutes. Add the garlic and ginger and cook for another minute.
Stir in the sweet potatoes, and add the vegetable broth and coconut milk. Simmer 25-30 minutes until the sweet potatoes are completely soft.
Puree with an immersion blender, or process in a regular blender in batches. Season to test with salt and pepper.
Top with sriracha, cilantro and chopped peanuts if desired.
*If you prefer a thicker soup, start with 2 cups of broth, and stir in more after blending until desired consistency is reached.Storage:This soup will keep for 3-4 days in the fridge or up to 3 months in the freezer in an airtight container.If you freeze it, the coconut milk may cause it to separate a bit when thawed, but a quick blitz with an immersion (or regular) blender should solve that.