Pre-heat the oven to 400°F. Pull one sheet of puff pastry out of the freezer and thaw it out in the refrigerator for about 30 minutes.
While the puff pastry is defrosting, make the filling: In a mixing bowl, combine the leftover mashed potatoes, shredded turkey, chili powder, parsley, cilantro, salt and freshly ground black pepper.
Once the dough has defrosted, use a little flour to roll out the dough to about 1/8 of an inch thick and cut it in half horizontally. Cut each half vertically into 3 equal pieces; you should have 6 squares. Place 1/3 cup of the potato mixture in the middle of each square.