1. Melt the butter or margarine in a large saucepan. Add the onions and cook for about.
2. 5 minutes until soft.
3. Add the squash, stock, potatoes, and paprika and bring to a boil. Lower the heat to low, cover the pan, and simmer for about 35 minutes until all the vegetables are soft.
4. Pour the soup into a food processor or blender and process until smooth. Return the soup to the pan and stir in the cream, if using. Season with salt and pepper and reheat slowly.
5. Stir in the chopped chives just before serving. Garnish each serving with a few whole chives.