Melt the butter in a large pot or saucepan over medium heat. Add the onion, garlic, and celery and cook until tender.
Stir in the broth, sweet potatoes, apple, ginger, curry powder, and ⅛ teaspoon each salt & black pepper.
Increase the heat to medium-high and bring to a boil. Once boiling, reduce the heat to a simmer, cover, and cook for 20 to 25 minutes or until the sweet potatoes are very tender.
Remove the ginger and puree the soup with a hand blender.
Add heavy cream and simmer for 5 minutes longer. Taste and season with additional salt and pepper if desired.
Top with crumbled bacon, croutons, and chives if desired.
