In a food processor, add the brown sugar, butter, flour, cinnamon and pumpkin pie spice.
Pulse until mixture becomes pea sized.
Stir in chopped pecans.
Cover and store in refrigerator until ready to bake.
Preheat oven to 350 degrees.
Pour topping over casserole.
Bake for 40-50 minutes or until casserole reaches desired doneness.