Fill a large pot with water and add a pinch of salt. Bring to a rolling boil over medium-high heat. Wash, peel, and cut the potatoes into chunks. Add potatoes to boiling water and cook for 15-20 minutes until fork-tender. Drain and cool.

In a mixing bowl, combine mayonnaise, sugar, vinegar, and mustard (if using). Whisk until smooth and creamy. Adjust seasoning to taste.

Once cooled, mash the potatoes in a large bowl until smooth, being careful not to over-mash. Fold in the dressing until fully coated.

Chop boiled eggs and add them with diced vegetables and optional apples or corn. Mix until evenly combined.

Cover and chill in the refrigerator for at least 30 minutes to let flavors meld.

Once chilled, stir gently to combine and serve in a bowl, garnishing with chopped vegetables if desired.