Make the salad: Preheat the oven to 400 degrees F. Brush a baking sheet with the olive oiland arrange the prosciutto in a single layer. Bake until the fat is rendered and the prosciutto is crisp, 12 to 14 minutes. Remove the prosciutto to a rack and let cool completely, then break into pieces and set aside.
Meanwhile, fill a large pot with cold water; add the potatoes and a pinch of salt. Bring to a boil, then reduce the heat to medium low and simmer until the potatoes are just fork-tender, about 15 minutes. (The potatoes will continue to cook when you remove them from the water, and you don't want a mushy potato salad!) Drain in a colander, then place the colander over the now-empty pot, off the heat, to allow the excess moisture to evaporate from the potatoes.
Make the dressing: In a large bowl, whisk the mayonnaise, scallions, sugar, paprika, mustard and vinegar. Taste and then season with salt and a few grinds of pepper.
Add the potatoes to the bowl with the dressing and gently toss. Refrigerate at least 1 hour. Sprinkle the crispy prosciutto on top before serving.
Photograph by Anna Williams
Recipe courtesy Sunny Anderson for Food Network Magazine