Cut the stem end off of the squash. Cut the squash in half. Remove seeds. Place cut-side down on a Pyrex baking dish and dish with an inch of water. Bake for 45 minutes at 350 degrees F or until squash is soft. Remove; let cool.
Peel and core an apple. Peel and dice carrot.
Place the chicken or turkey stock in a large saucepan. Add apple, squash, carrot. Bring to a boil, then simmer, uncovered or partially covered, for 30 minutes or until vegetables and fruit are tender.
Remove from heat and allow to cool.
Pour cooled soup and vegetable mix into blender and puree on low setting until smooth.
Return mix to saucepan and heat until desired temperature. Pour into bowls and garnish with feta chunks or pumpkin seeds as desired. Any remaining soup should be refrigerated until reheated and enjoyed.