Add potatoes to a large pot and cover with one inch of water. Boil for 15-20 minutes, or until fork tender. Drain and set aside to cool.
Meanwhile, cook bacon in a large skillet over medium heat for 7-8 minutes. Remove the bacon from the skillet using a slotted spoon, leaving the drippings in the skillet. Keep the skillet on medium heat and add the chopped onion. Cook until tender, about 2-3 minutes, stirring often. Add the garlic and continue cooking for an additional 30 seconds, or until the garlic becomes fragrant.
Peel the potatoes and cut them into ½-inch chunks.
Pour in the broth and vinegar and add the mustard, sugar, salt, and pepper. Whisk until well combined. Bring the sauce to a boil and then reduce heat to low. Simmer for 5 minutes, or until the liquid has reduced by half. Remove from heat.
Add the potatoes to the vinegar mixture along with the oil and toss until they are completely coated. Transfer the potatoes to a serving platter. Finely chop the cooked bacon and then sprinkle it over the potatoes along with fresh parsley or chives, if desired.
