Cook the potatoes: Wash the potatoes thoroughly and place them in a large pot. Cover with cold water and add a pinch of salt. Bring to a boil over medium-high heat, then reduce to a simmer. Cook until the potatoes are tender when pierced with a fork, about 15–20 minutes depending on size. Drain the potatoes and let them cool slightly, then peel if desired and slice them into 1/4–1/2 inch thick rounds or cubes.

Cook the bacon and onion: While the potatoes are cooking, heat a large skillet over medium heat. Add the diced bacon and cook until crisp, stirring occasionally. Remove the bacon pieces with a slotted spoon and set aside, leaving the rendered bacon fat in the skillet. Add the chopped onion to the bacon fat and sauté for 3–4 minutes until the onion becomes soft and translucent, absorbing the smoky flavor of the bacon.

Make the dressing: Reduce the heat to low. Stir in the apple cider vinegar, sugar, Dijon mustard, salt, and black pepper into the onion and bacon fat mixture. Cook for 1–2 minutes until the sugar dissolves and the dressing is slightly thickened and glossy. Taste and adjust seasoning if needed.

Combine the salad: Add the warm sliced potatoes and the crispy bacon to the skillet with the dressing. Gently toss everything together, making sure the potatoes are evenly coated with the flavorful bacon-onion dressing. Allow the salad to sit in the skillet for 3–5 minutes so the potatoes absorb the dressing and become slightly warm and tangy.

Finish and serve: Transfer the potato salad to a serving dish. Sprinkle the chopped fresh parsley over the top for color and freshness. Serve warm or at room temperature. This salad pairs beautifully with grilled sausages, roasted meats, or as a hearty side at any family gathering.