Potato salads are like a favorite relative: they can be plain or they can be fancy, but it's nice when they show up for a picnic.
This particular salad always reminds me of my Aunt Stell, who used a blue rinse on her snow-white hair. Mostly, the blue enhanced the white, but on one occasion, she mismeasured and her coif turned purple. At age 6, I loved the result. At 60-plus, she hated it.
Well, even potatoes can be purple. But naturally so. Incas were serving them long before Pizarro came along to help himself to their gold.
Now purple potatoes are in most supermarkets, looking just like ... potatoes. They have the same coloring compounds that make cabbage red, however. And like red cabbage, they get brighter in an acid dressing. (Creamy mixtures mask the color.)
The potatoes are positively brilliant when seasoned with this see-through lime and orange juice dressing. I think Aunt Stell would've loved purple in her salad as much as I liked it on her hair.