Cook the lentils in plenty of salted water for about 10 minutes until just soft, drain.
In the meantime, peel and chop the onions, garlic and apples and sauté in the olive oil for 5 minutes.
Add the lentils and season with cumin, herb salt and pepper.
Deglaze with vegetable stock, remove from the heat and leave to stand for 10 minutes.
Wash and trim the lettuce and cut into bite-sized pieces. Add the crème fraîche to the lentils, add balsamic vinegar to taste and stir well. Mix the lentil salad with the lettuce, and stir in the finely chopped chives.