First wash up your potatoes. I like to use classic small red potatoes. Cut them up in quarters if they are small, or in eights if they are the larger ones.
Place them in a pot with a few pinches of salt and bring to a boil.
While you are at it, grab some eggs and hard boil them. I got a nifty tutorial for you on how to make the easiest and most perfect hard boiled eggs every time.
While that's working for you, finely dice some celery.
When your potatoes are juuuuuust fork tender, dump them into a colander and let them cool. In fact you can always do this the night before as well.
Place the potatoes in a bowl and crumble up your eggs right on top of there. I just mushed the eggs with my hand, but feel free to do this with your fork if you would like.
Chop up a bunch of scallions (about 3/4 of a cup)... I like it really scalliony because I feel it really brings out the flavor in the potatoes. Add the scallions to the heap as well.
Now add 3/4 cup of sour cream, 3/4 cup of mayo, 1/4 cup of dijon mustard and salt and pepper. Mix everything with a big spatula or your hands. I prefer to use my hands because you get the "dressing" distributed a bit more evenly this way. Check for seasonings and see if you need it zestier, saltier or if it's just right!
Garnish with scallions and enjoy!