For the soup
In a soup pot, sweat the onions, celery, leeks, and garlic in a small amount of the stock until translucent. Add the remaining stock, potatoes, cinnamon, and nutmeg. Simmer until the potatoes are tender. Discard the cinnamon stick and puree the soup, using a food processor, blender, or immersion blender, until smooth and strain through a fine-mesh sieve. Chill from 8 to 12 hours, allowing the flavor to develop. Add the syrup, salt, and milk to the cold soup.
For the garnish
Serve hot or cold and garnish with the whipped cream, almonds, and raisins