Stir together first 3 ingredients.
Place puff pastry sheet on a lightly floured surface; roll out fold lines. Spread brown sugar-and-pecan mixture in a 5-inch circle in center of puff pastry sheet. Place Brie round on top of pecan mixture.
Wrap puff pastry around Brie, pinching to seal tightly, and place on an aluminum foil-lined baking sheet, folded side down.
Bake at 400° for 25 minutes or until pastry is lightly brown. Cool 10 minutes on baking sheet. Serve warm with French baguette slices, apple and pear slices, and assorted crackers.