6 stems of rhubarb, about 700 g 8 dl of water 2 dl sugar 4 tbsp potato flour Rinse the rhubarb and cut them into pieces. Boil water and sugar and add rhubarb. Boil until rhubarb soften. Mix the potato flour with a small amount of water and add to the kettle in a thin strip with gently stirring. Let it boil fast. Pour the soup into the bowl to cool and sprinkle some sugar on the surface. Serve with milk or vanilla sauce.