From Just Food:

Butternut squash and apples are a classic combination, and this soup combines them perfectly.

Butternut Squash Apple Soup

1 yellow onion, chopped
1 rib of celery, chopped
1 carrot, chopped
1 Tbsp butter
1 butternut squash, peeled, seeds removed, chopped
1 tart green apple, peeled, cored, chopped
(squash and apple should be at a 3 to 1 ratio)
3 cups vegetable or chicken broth
Pinches of nutmeg, cinnamon, salt and pepper

Combine butter, onion, celery, and carrot in large saucepan. Cook for 5 minutes. Add squash, apple, and broth. Bring to boil. Simmer for 10 minutes or until squash is soft. Puree. Add spices to taste.

Serves 4-6.

Source: Simply Recipes