Transfer the potatoes to a large pot and fill with enough cold water to cover by at least 2 inches. Set over high heat and bring to a boil. Cook for approximately 10 minutes, or until you are just able to pierce them with a fork (try not to overcook your potatoes). Drain and set aside to cool.
Meanwhile, as the potatoes boil, cook the bacon. Add the chopped bacon to a large skillet and set over medium-high heat. Once the bacon is hot and sizzling, reduce heat to medium-low and cover with a lid. Cook low and slow, stirring occasionally. Once the bacon pieces are golden, remove the lid and allow them to cook until the desired doneness is reached. Remove the bacon using a slotted spoon to a plate lined with paper towels. Reserve approximately 2-3 tablespoons of bacon grease.
Once the potatoes are cool enough to handle - but still warm - gently peel. You can do this using your hands (the skin should rub and peel right off), or use a small paring knife. You may also leave the skin on if preferred. Chop the potatoes into small, equal-sized cubes or slices.
Return the skillet with the bacon grease to medium-high heat. Add the minced onion and cook, stirring occasionally for 5-6 minutes, or until onions are softened. Add the minced garlic and cook for 1 minute more.
As the onion is cooking whisk together the apple cider vinegar, white vinegar, water, coarse brown mustard, and granulated sugar in a small bowl.
Once the onions are soft and translucent, add the bacon back to the skillet and add the vinegar mixture, mixing well to combine. Once heated, add the potatoes and parsley and gently mix well to combine. Garnish with additional parsley, to taste, and season with salt and pepper. Enjoy!