Heat oil in heavy large saucepan over medium-high heat. Add onion and minced ginger and sauté until onion is translucent, about 5 minutes. Add chicken stock and sliced carrots. Cover and simmer until carrots are tender, about 30 minutes.
Working in batches, puree mixture in blender or processor. Return soup to saucepan. Or alternately, remove from heat and puree with immersion blender. Mix in orange juice, then half and half. Cook over low heat 5 minutes. Mix in ground cinnamon and ground nutmeg. Season soup to taste with salt and pepper. Bring to simmer before continuing, thinning with more stock if desired. Ladle soup into bowls and serve!
Can be prepared 1 day ahead. Cover and refrigerate.