Cook the potatoes: Add potatoes, skin-on, to a large pot filled with cold water. The potatoes should be approximately evenly sized; if some potatoes are larger, cut them in half. Salt the water well. Bring to a boil then simmer until just tender (about 15–20 minutes, depending on the size and type of potatoes).
2 pounds (900g) waxy potatoes
While the potatoes are cooking, prepare the dressing:
In a small pot, bring the broth to a boil then simmer until reduced by half in volume (you should end up with about ½ cup).
1 cup (240ml) beef broth
Dice the bacon, finely dice the onion, and the herbs.
6 ounces (170g) thick-cut bacon, 1 small/medium red onion, 2 tablespoons chopped fresh parsley, 2 tablespoons chopped chives
Add the bacon to a cold skillet and turn the heat to medium (the fat should slowly render from the bacon). Cook until browned and crispy. Transfer the bacon to a plate. Leave about 1–2 tablespoons of bacon fat in the pan (pour off excess if needed).
Add the chopped onion to the bacon fat and sauté over medium heat for about 3–4 minutes, or until soft and translucent.
Add 2/3 of the bacon back to the pan, then add the beef broth, vinegar, sugar, and mustard to the onions in the pan. Stir and bring to a simmer. Let it simmer gently for 1–2 minutes to blend the flavors, whisking vigorously to combine all the ingredients. Take the pan off the heat and whisk in the oil until the dressing is slightly emulsified. Season with salt and pepper to taste. The dressing will taste a little bit on the sour side, but the sharp flavor will mellow when combined with the potatoes.
¼ cup (60ml) white wine vinegar, 3-4 teaspoons sugar, 1 tablespoon Dijon mustard, 3 tablespoons neutral-tasting vegetable oil
Meanwhile, the potatoes should be ready.
Prepare the cooked potatoes: Drain the potatoes and let them cool slightly. They should still be very warm; if they are too hot to handle, you can hold the potato through a paper towel and peel it with a small paring knife. Slice the potatoes into 1/2-inch (1 cm) thick rounds/dice (as you wish). While still warm, transfer to a large mixing bowl.
Combine: Pour the warm dressing over the sliced potatoes (ideally they should still be warm, because this way they will absorb the dressing better) and toss gently with a silicone spatula to combine. Stir in chopped herbs. At this point, the salad will be a little bit too runny, but the potatoes will absorb the dressing in a couple of minutes.
Let the salad stand for 15–20 minutes, gently stirring it from time to time, until the dressing is absorbed. Crumble the remaining bacon on top.
Serve warm or at room temperature.
Enjoy!