Melt the butter in a medium saucepan over medium-low heat. When the butter begins to sizzle, stir in the flour; cook, stirring, for 2 minutes. Gradually stir in the chicken broth and apple juice.

Increase the heat to medium and cook, stirring constantly, until the broth begins to simmer. Add the squash and bring to a boil. Reduce heat and simmer for about 20 minutes, or until squash is very tender.

Working in batches, carefully puree the hot mixture in a blender until smooth. The blender should never be more than half full of a hot liquid, and make sure to hold the lid down with a folded kitchen towel in hand.

Return the soup to a saucepan and place it over low heat. Add the nutmeg and cream and heat through. Add salt, to taste, and garnish with parsley or cilantro, if desired.