1Cook potatoes in chicken stock until soft. Set aside, do not drain.
2Put potatoes in the work bowl of a food processor in batches. Add 5 cups of chicken stock from the potato cooking pot. Puree until smooth.
3Half the leeks lengthwise, and soak in water to clean. Finely slice. Saute in butter until transparent. Add white wine, and cook for 3 minutes.
4In a soup pot, combine remaining cup of chicken stock from the potato cooking pot and sauteed leeks. Stir in pureed potatoes, and bring to a simmer. Season with salt and white pepper. Cook to desired consistency, adding more stock if necessary. Garnish with parsley.