Purple Carrot Soup

Heat olive oil in a pot over medium heat and cook celery, shallot, ginger, and garlic until fragrant, about 5 minutes. Add carrots and potatoes; mix to combine. Pour in 3 cups vegetable broth and slowly bring to a boil. Reduce heat and simmer until carrots and potatoes are soft, about 15 minutes.

Puree soup with an immersion blender until smooth, adding enough remaining broth to reach the desired consistency.

Garnish with pistachio nuts and sour cream.