Preheat oven to 400F
Lay your puff pastry sheet on a parchment lined baking sheet. Scour (cut a line) along the inside of the edge of the dough, about 1 inch in from the outside.
Mix together the melted butter, pumpkin pie spice, and brown sugar. Using a pastry brush, brush the butter over the entire puff pastry sheet.
Lay your pear slices into the middle of the puff pastry, slightly overlapping as you go. My tart was big enough to go three slices across and 7 slices down.
Pour the remaining butter mixture over the pears and brush to cover.
Sprinkle with pecans if desired.
Bake for 15-18 minutes or until puff pastry is fully cooked and browned.
Remove from oven and cut with pizza cutter into squares.
Sprinkle with powdered sugar if desired.
Serve with ice cream for an extra special treat!