How to Make It
Prepare Crust: Preheat oven to 350°. Pulse flour and next 3 ingredients in a food processor 8 to 10 times or until thoroughly combined and pecans are finely chopped; add butter, and pulse 8 or 9 times or until mixture resembles coarse meal. Line bottom and sides of a 13- x 9-inch pan with aluminum foil, allowing 2 to 3 inches to extend over sides; lightly grease foil with cooking spray. Press mixture onto bottom of prepared pan.
Bake at 350° for 20 to 25 minutes or until lightly browned. Cool completely on a wire rack (about 25 minutes).
Prepare Filling: Bring syrup and next 4 ingredients to a boil in a large saucepan over medium heat, stirring constantly until butter melts and mixture is smooth; boil, stirring constantly, 1 minute. Remove from heat, and stir in vanilla and 3 cups coarsely chopped toasted pecans. Pour hot filling over cooled crust.
Bake at 350° for 14 to 16 minutes or until filling bubbles in center. Cool bars completely in pan on a wire rack (about 1 hour). Chill bars 1 hour before cutting.