Preheat oven to 350 degrees. Prepare a 9x13 baking dish, lining it with foil and spraying with baking spray.
Preparation is done with a large food processor.
In your food processor, pulse the pecans until ground. Then, add in the flour, sugar, baking powder and salt to the processor. Pulse until well combined.
Add in the eggs and butter. Run processor until thick dough is formed and everything is well combined.
Pour the dough into your pan and spread out evenly along the bottom.
Wipe out your food processor and add in the cream cheese and pumpkin. Pulse until nice and creamy, with no lumps.
Add in the eggs, vanilla and melted butter. Mix again.
Add in all of the spices and slowly add in the powdered sugar, pulsing as you go, and mix until everything is well combined and no lumps are remaining.
Pour the filling into pan over crust.
Bake 40-50 minutes. A toothpick should come out with just a few crumbs. Be care not to over bake.