I said "you don't make it, you buy it from the store!"
Here's my recipe for potato salad:
The only cooking required is to boil the eggs and potatoes. You can certainly do that in cast iron if you want to, but not required*.
*Normally, cooking food in cast iron has a significant impact on taste and consistency. Boiling is an exception; it has no effect.
I recommend red potatoes; They're less starchy. Others use Yukon gold potatoes.
You probably already know this, but cut the potatoes into cubes before boiling, and peel/slice the eggs after boiling. Peeling potatoes optional.
Use 4 parts olive oil mayo to 1 part mustard. For example, 1 cup to 1/4 cup.
Mix in eggs, potatoes, chopped pickles or pickle relish*, and green olives. Add paprika.
*Could be sweet or dill, depending on your preference.
Some like to add chopped onions and/or celery. I'm fine without it.