Stir together brown sugar, cinnamon, chopped pecans, and whiskey.
Place puff pastry on a lightly floured surface. Spread brown sugar and pecan mixture in a 5-inch circle in the center of the puff pastry sheet.
Place brie round on top of pecan mixture.
Wrap puff pastry around Brie, pinching to seal tightly.
Place on a sheet tray folded side down and bake at 400 degrees for 25 to 30 minutes or until lightly brown.
Cool for 10 minutes. Serve warm with sliced pears, apples, grapes, and assorted crackers.