Heat the oil in a large saucepan.

Add onion and garlic and cook for around 5 minutes or until the onion is softened but not browned.

Add the celeriac, pour in the stock mixture, bring to the boil over a high heat, then reduce the heat and cover the pan.

Cook the soup gently for 10 minutes or until the celeriac is tender.

Add the spinach to the soup and stir well. Increase the heat and bring back to the boil then remove from the heat to cool.

When slightly cooled, puree in a blender until smooth and thick.

Reheat the soup if necessary, then stir in a little nutmeg, salt and pepper to taste.

Ladle into warm bowls, swirl a spoonful of creme fraiche into each portion and garnish with fresh chives.

Serve immediately