Wash the potatoes and cook in boiling water for about 20 minutes. Drain, rinse with cold water and remove the skin. Clean, wash and slice the celery. Clean, wash and cut carrots into sticks.
Cook the lentils in boiling water for about 10 minutes. Add celery and carrots for the last 4 minutes. Drain. Cut potatoes into slices and fold into the vegetables. Wash, clean and drain the lamb's lettuce.
Halve the bacon slices once crosswise. Peel and halve the shallots. Heat the oil, crisp up the bacon and take it out. Sauté shallots briefly in hot bacon fat. Add 250 ml water, bring to the boil once.
Add broth and vinegar. Season with salt and pepper. Mix the stock with the salad. Add lamb's lettuce and bacon and fold in as well. Season to taste with salt and pepper.