Cook until potatoes are thawed and broken apart . Add the vegetable stock and boil for a few minutes until potatoes are very tender . Add the spinach and cook for a few minutes longer , until spinach is just tender . Transfer soup to a food processor , in batches if necessary , and process until relatively smooth ( it does n't need to be homogenous ; the spinach and potatoes just need to be broken up into flecks . ) Return to the pan and add the lentils .

Question: Why do you not have to process the soup until it is very smooth ?
Answer: All soups should be served this way because this is the best way to make them , so you 're not just drinking up liquidThe soup is best when there 's some full consistency to it and there 's still a bite to the dishSoups in general can be too smooth and they do n't taste goodSoup when smooth is more like baby food and that 's unappetizing