How to Make It
In a large pot, heat the oil over moderate heat. Add the onion and sauté for 5 minutes. Add the garlic, ginger, lemongrass and curry paste and cook for 3 minutes. Add the pumpkin puree and broth, stirring to incorporate, then season with salt, and bring to a boil. Reduce the heat to low and simmer for 20 minutes. Stir in the coconut milk and lime juice and let cool for 10 minutes.
Transfer the soup to a blender (or use an immersion blender in the pot) and puree until smooth. If needed, add additional water or broth to reach the desired consistency. Return the mixture to the saucepan. Serve warm and garnish with fresh cilantro and thinly sliced Fresno chiles.