No mustard in potato salad.
People who do that are certified nutcases.
Euph's Potato Salad:
5 lbs. of russets
2 leeks, cleaned and chopped
3-4 stalks of celery, cleaned and chopped
1 large green (bell) pepper, cleaned, seeded, and chopped
1/4 cup red wine vinegar, or to taste
2-3 cups of mayo, or to taste
1 cup fresh dill
Kosher salt and fresh ground pepper to taste
Cook the potatoes in their jackets, gently. When fork tender, peel and slice into bite-sized pieces into a large bowl while hot, using a towel to keep from burning your widdle fingers.
WHILE THE POTATOES ARE STILL HOT, add the vegetables, vinegar, mayo, dill, seasonings.
Mix gently.
The mayo soaks up into the potatoes as they cool, leaving you with salad, not soupy, mayo-infested mess.
No mustard in that recipe.
At all.
THAT, my friends, is potato salad. Nothing else even comes close.