Wash the small red potatoes and place them in a large pot. Cover with water, add salt, and bring to a boil.

Cook for 12-15 minutes until fork-tender but firm. Drain and let cool slightly.

Cook bacon in a skillet over medium heat until crispy. Remove and drain on paper towels.

Sauté diced yellow onion in the skillet with bacon fat until translucent.

Whisk in stone ground mustard, sugar, salt, and black pepper into the onions, then add apple cider vinegar. Cook briefly to thicken.

Slice the potatoes into half-rounds and add them to the skillet with the dressing. Crumble the bacon on top and toss gently.

Fold in freshly chopped parsley and serve warm or let chill for 30 minutes to enhance flavors.