Heat oven to 350°F. Spray 15x10x1-inch baking pan with nonstick cooking spray.
In medium saucepan, combine pecan pieces and butter; cook and stir over medium heat until butter is melted and pecans are toasted. Remove from heat. Stir in brown sugar, whipping cream, flour and cinnamon.
Place one tortilla on sprayed pan. Spread heaping 1/3 cup pecan mixture evenly over tortilla. Repeat layers two more times. Top with a fourth tortilla. Make another stack on same baking pan using remaining 4 tortillas and pecan mixture.
Bake at 350°F. for 15 minutes. Cool slightly; cut into wedges. If desired, serve topped with scoop of vanilla ice cream.