Peel and finely chop the onion. Heat the oil in a pot and fry the onions in it until transparent. Add lentils, also fry briefly and deglaze with stock and vinegar. Bring to the boil, cover and cook over medium heat for 10-12 minutes. Season the finished lentils with salt and pepper and let them cool down.
In the meantime, clean and wash the chicory and cut the bitter stalk into wedges. Remove the outer chicory leaves. Cut the remaining chicory into strips. Wash and quarter the apples and cut out the core. Cut the apple quarters into slices and sprinkle with lemon juice. Wash the chives, dab dry and cut into small rolls. Line 4 plates with whole chicory leaves in a star shape. Mix apples, chicory strips and lukewarm lentils, season to taste with salt, pepper and vinegar and arrange on the chicory leaves. Sprinkle with chives.
Cut the apple quarters into slices and sprinkle with lemon juice. Wash the chives, dab dry and cut into small rolls. Line 4 plates with whole chicory leaves in a star shape. Mix apples, chicory strips and lukewarm lentils, season to taste with salt, pepper and vinegar and arrange on the chicory leaves. Sprinkle with chives. Serve garnished with apple slices as desired