Cut the endive salad into fine strips and wash thoroughly, then drain well in a sieve.
For the marinade, dice the onion very finely and mix it with the mustard and herb vinegar. Season to taste with salt, pepper and a little sugar. If the marinade is too strong, it can be made milder by adding a little water. Finally mix in the oil. Add the endive salad just before serving and mix well.
The light bitter substances of the endive salad mix wonderfully with the onion and mustard marinade. We also have potato and zucchini buffers that are topped with Limburg cheese and coated with a mixture of tomato paste and horseradish.