Flour a work
surface; roll out puff pastry to 1/8" thick and cut into 31/2 X 31/2"
squares. Dock with a fork or docker. Place on floured parchment paper,
cover & refrigerate for 30 minutes. In the meantime in a stainless
steel bowl, combine potatoes with cheese, mayo, vinegar, seasoning and
herbs. Mix until all ingredients are combined. Remove dough from refrigerator,
place on work surface. Mound a small amount of potato salad in the center
of each puff pastry square. Brush edges with egg wash. Fold dough over
from one point to the other, making a triangle. Seal the edges by pressing
down with a fork, making an airtight seal; brush the popover with egg
wash. Bake at 400° until puff pastry is golden brown, about 25 minutes.
Cool on a wire rack.