Boil or steam 1.3 kg organic baby potatoes with their skins on until tender, about 15 - 20 min. Add 1 bay leaf and, if available, 3 black peppercorns to the water and cook along with the potatoes.
Meanwhile, peel and halve 3 red onions.
Finely dice half of the onions and cut the other half into thin slices.
Heat a small pan with 1 tbsp canola oil over medium heat and sweat the diced onions for about 5 min until soft. They shouldn't brown; reduce the heat if necessary.
Deglaze the onions with 250 ml vegetable broth and bring to a gentle boil. Add 3 tbsp white balsamic vinegar, 1 tbsp hot mustard, 1 tbsp medium-hot mustard, 1.5 tsp sugar, 1 tsp salt and some black pepper, stir and bring briefly to a boil.Carefully taste the hot sauce and adjust the seasoning with a little more vinegar, salt or sugar if needed (see Tips & Tricks).
Remove the pan from the heat and stir in 2 tbsp canola oil.
As soon as the potatoes are done, cut them in half crosswise with the skin on and place them in a large bowl.
Pour the hot sauce over the still hot potatoes, add the remaining onions and gently mix everything (see Tips & Tricks).
Let the potato salad with the mustard dressing cool, stirring every now and then.
Shortly before serving, clean the herbs, chop finely and fold into the potatoes.
Season to taste with salt and pepper and enjoy.