How to Make It
In a large saucepan, heat the oil until shimmering. Add the onions, garlic and a generous pinch of salt and cook over moderate heat, stirring occasionally, until softened and just starting to brown, about 10 minutes. Add the stock, squash and nutmeg and bring to a boil. Simmer over moderate heat, stirring, until the onion is very soft, about 5 minutes. Stir in the pumpkin ice cream until melted.
Working in batches, puree the soup in a blender until smooth. Return the soup to the saucepan and reheat. Season with salt and white pepper. Ladle the soup into bowls and swirl in dollops of whipped cream. Top with toasted pumpkin seeds and serve.