Fill a large pot with cold water, add a pinch of salt, and drop in the whole potatoes. Bring to a gentle boil and cook until a fork slips in easily—about 15 minutes.

While the potatoes simmer, heat a skillet over medium heat and fry the diced bacon until golden and crisp. Use a slotted spoon to transfer bacon to a paper towel, leaving behind the rendered fat. Drain the potatoes in a colander, then let them cool just enough to handle.

In the same skillet over low heat, warm the bacon fat and stir in the chopped onion. Sauté until translucent—roughly 2 minutes—then whisk in vinegar, chicken broth, Dijon mustard, and sugar.

Pour the hot vinegar dressing over the potatoes, stirring gently so every piece soaks up the tangy flavor. Fold in the crispy bacon bits, reserving a few for garnish. Season generously with salt and freshly ground pepper.

Sprinkle chopped parsley and sliced green onions on top for a burst of color and freshness. Serve warm straight from the pot or transfer to a bowl.