This soup can be prepared with either homemade fresh or frozen as well as canned pumpkin purée.

Melt butter over medium heat in a large casserole saucepan. Add leek and cook 5 Minutes over low heat. Stir occasionnaly with a wooden spoon.
Add potato, pumkin purée and broth. Bring to a boil, reduce heat and simmer for about 20 Minutes until the vegetables are very tender.
Puree the soup in a blender or with an immersion blender. Add enough cream for the desired consistency, nutmeg, Cayenne pepper, basil and salt to taste.