Soak the endive salad in warm water for about 10 minutes and allow to drain. Mix the feather white, the onion and the chives into a sauce and season with salt, pepper and sugar.
Put the salad in a bowl and pour the sauce over it. Melt the bacon in a pan, pour over the salad and season. Mix everything well.
Serve this salad as an accompaniment to dishes or with bread, butter and cheese as a snack.