Rinse the lentils well with cold water in a colander. Peel the potatoes, cut in half lengthways and cut into thin slices. Cut the cabanossi into thin slices. Heat the olive oil and fry the cabanossi slices in it. Add the potato slices and tomato paste, sauté for approx. 2 minutes. Pour in the stock, add the lentils, cook everything over a medium heat for 12-15 minutes. Clean and slice the spring onions. Add about 5 minutes before the end of the cooking time. Season the soup with vinegar, Tabasco, salt and white pepper to taste.
P.S. if you want to use normal plate lenses instead of the red lentils, the cooking time is extended to approx. 45 minutes.