Linsensuppe Mit Frankfurter

• 1 lentils
• 1 leek
• 1 carrot
• 1 celery
• 1 onion
• 2,400 ml saucepan bring
• 1,400 ml water
• 1,400 ml water (boil)
• 5 ml vegetable oil
• 5 gr unbleached flour