Heat the water, stir in the broth, honey or sugar and mustard and allow to cool. Add vinegar and season with salt and pepper. 1 - 2 pressed garlic cloves in this sauce taste very delicious.
The easiest way is to let the seasoned broth cool down in a 0.75 liter bottle (juice bottles are great). I then fill it up with the balsamic vinegar.
I only add the olive oil and possibly herbs when preparing the salad.
The sauce can be stored in the refrigerator for at least 2 weeks. However, it also tastes lukewarm with rocket!