Peel, wash and chop the carrots. Clean, wash and cut the celery into thin pieces. Peel shallots and cut into rings. Finely dice bacon. Clean mushrooms and possibly halve them.
Heat up the lard and leave the bacon in it until crispy. Add mushrooms, fry for about 3 minutes and take out. Steam shallots, carrots and celery in bacon fat for about 5 minutes. Add lentils. Deglaze with stock and vinegar, cook for about 10 minutes.
In the meantime clean and wash the salad and cut it into bite-sized pieces. Arrange on a plate with the mushrooms. Season the lentil marinade with salt, pepper and sugar. Pour over the salad while still hot.
Pluck the thyme leaves from the stems and sprinkle over the salad.