When the pastry is thawed, sprinkle a little flour on the parchment and unroll the pastry on top.  Use a rolling pin to roll the pastry until it is the exact size of the parchment, trimming if necessary.  Every few rolls, lift up the dough and sprinkle a little flour underneath. Slide the dough and parchment onto the jelly roll pan. Use a fork to dock the dough with holes, leaving a one-inch border clear, without any holes.

In a small bowl, combine the sugar, cinnamon and cardamom. Cut two large pieces of the nectarines off the pit and then slice into very thin slices, thinner than ¼-inch.  I usually use only the larger slices for the tart and nosh on the smaller ones.  Sprinkle a little more than half of the cinnamon, sugar and cardamom mixture on the dough, leaving the border clear.  Place the nectarine slices on the pastry overlapping in rows on the short side of the dough.  I alternate the direction the fruit slices are facing for each row.  Sprinkle with the remaining cinnamon, sugar and cardamom.  Bake for 25 to 30 minutes, or until the pastry is golden.

Slide the pastry onto a cooling rack.  Cut into squares or rectangles.  Serve warm or at room temperature.