Preheat oven to 350 degrees. Spray a baking sheet with cooking spray and set aside.
In a food processor, combine flour, oats, and brown sugar. Pulse to combine. Add in the cubed cold butter and pulse to form a fine crumb. Pour into baking sheet and press into bottom of pan. Bake for 20 minutes, until light brown.
While the crust bakes, combine pumpkin filling ingredients in a large bowl and beat with hand mixer until smooth. Pour over crust and carefully return to oven (pan will be full). Bake for 30 minutes.
Meanwhile, prepare the pecan topping. Add brown sugar, chopped pecans, and flour to a bowl and stir to combine. Cube the butter and add to mixture. Use fork or hands to combine. Sprinkle over the top for the pumpkin bars and return to oven for an additional 10-15 minutes or until knife inserted in middle comes out clean.
Cool the pumpkin pie bars completely before cutting and serving.
Video
Notes
These bars need to chill completely before cutting. Make a day or two in advance and refrigerate until ready to serve. See post for freezing instructions.