In a large saucepan over a medium heat warm a little oil then add the grated carrot and turnip. Season and cook and stir for several minutes.
Add the water and stock cubes and bring to the boil. Reduce the heat and simmer gently for 15 to 20 minutes. Blend using a handheld liquidiser until smooth. Return to the heat and bring again to the boil. Once boiling remove from the heat and serve in warmed bowls.