- Heat the butter in a large saucepan. Add the spring onions, celery and potato. Stir and put on the lid. Cook for 10 minutes, stirring a couple of times. Pour in the vegetable stock and cook for 10 – 15 minutes until the potato is soft. Add the spinach and cook for a couple of minutes until it loses it raw flavor and well cooked.Use a hand blender to blend it into a smooth soup. Then take it into a bowl and garnish with cream and almond.serve hot.