Cut waxy potatoes into 1-inch chunks. Boil in salted water for 12-15 minutes until fork-tender but still firm. Drain well and transfer to a large bowl.
2 lbs waxy potatoes
Fry bacon strips in a skillet over medium heat for 8-10 minutes until crisp. Remove bacon, chop into bits, and reserve 2-3 tablespoons of bacon fat in the pan.
6 strips bacon
Add diced onion to the reserved bacon fat in the skillet. Cook for 3-4 minutes until translucent and slightly soft.
1 medium yellow onion, 6 strips bacon
Add vinegar, chicken broth, sugar, and optional mustard to the skillet with onions. Stir and bring to a simmer for 2-3 minutes until sugar dissolves.
0.5 cup white vinegar, 0.5 cup chicken broth, 2 tbsp sugar, 1 tbsp Dijon mustard, 1 medium yellow onion
Pour the warm dressing over the hot potatoes. Add chopped bacon and fresh parsley. Toss gently to coat. Let rest off heat for 10 minutes so flavors meld before serving warm or at room temperature.
2 lbs waxy potatoes, 6 strips bacon, 2 tbsp fresh parsley, 0.5 cup white vinegar, 0.5 cup chicken broth, 2 tbsp sugar, 1 tbsp Dijon mustard