Step 1

Heat the oil in a Dutch oven or soup pot over medium heat until shimmering. Add the onion and celery and cook until the vegetables are soft and tender, 6 to 8 minutes. Stir in the garlic and cook for 1 minute more. Add the sweet potatoes, coriander, paprika, sage, salt, and pepper; stir to combine; and cook for 1 minute.

Step 2

Add the stock and bring to a boil. Reduce the heat to maintain a simmer and cook until the sweet potatoes are tender, 10 to 15 minutes. Transfer about 2 cups of the soup, broth, and vegetables to a blender or food processor and purée until smooth. Stir the purée back into the soup and serve immediately.