2 leeks, white and light green part only, sliced
In a large pot, melt the butter, and sweat the leeks until half their volume, about 5 minutes. Add the garlic, and continue to saute for 1 minute. Season with salt and pepper, add the curry powder and the cinnamon and toast for 2 minutes. Add the squash and apples, stirring well to ensure they are evenly coated by the spices. Saute for 5 minutes. Pour in the broth, bring to a boil, and taste for seasoning. Continue to simmer the soup until apples and squash are well-softened, about 25 minutes. Puree with an immersion blender till smooth, or run through a food processor in batches. taste for seasoning.
Serve with a drizzle of sour cream and a sprinkle of chives on top.