Soak the lentils in 2 liters of water overnight, then bring to the boil and then simmer for half an hour, then add all the ingredients without spices and without sausage and simmer again for 45 minutes - 60 minutes.
Then season with salt, pepper, sugar, plenty of thyme and the fruit vinegar. Then, if it has the right seasoning, add the cornstarch (mixed in 2 tablespoons of water) to the soup and then add the sausages, stir in again, bring to the boil, done!
I prefer to eat this soup a day later (it just tastes better) and so I also add the sausages a day later (otherwise they will be too dry). Good Appetite!