Wash and scrub the red potatoes under cold water.
Cut the potatoes into halves or quarters, depending on their size.
Place the potatoes in a large pot and cover them with cold water.
Add a pinch of salt to the water and bring to a boil.
Cook the potatoes for 15-20 minutes, or until fork-tender.
Drain the potatoes and let them cool for about 10 minutes.
In a large bowl, combine mayonnaise, Dijon mustard, and apple cider vinegar.
Add chopped celery, red onion, and bell pepper to the dressing.
Once the potatoes are cool, add them to the bowl and gently mix.
Season with salt and pepper, then garnish with fresh parsley.