First mix the dressing. Beat the mustard, vinegar and oil with a magic wand or a blender. Then add the herbs and shallot cubes and season to taste.
Cook the cleaned beans in boiling water with plenty of salt for about 5 minutes. Drain, quench and immediately, while still hot, mix with the marinade. Let cool down, mixing carefully over and over again. Possibly season again.
Tip: TK 8 herb mixture is an excellent herb. Since these herbs are very productive, about 1 tablespoon is sufficient here.