Preheat oven to 350 and line a 9x9 inch pan with aluminum foil and spray with cooking spray. Also line a baking sheet with parchment paper or foil and spray with cooking spray. Set aside.
In a food processor combine flour, brown sugar, salt, and diced butter. Blend until a coarse meal forms. Add pecans, and oats and continue to pulse until combined and coarse. Moist, but not clumping.
Press 3 1/2 cups of the mixture into the bottom of your 9x9 inch pan. Put remaining crumbs on the baking sheet and bake for 8-10 minutes until golden stirring once. Remove from oven. Bake the crust 10-12 minutes and remove from oven. Keep the oven on while preparing filling.
Beat together cream cheese and pumpkin until smooth. Add sugar, egg, cinnamon and sugar. Spread over the crust. Bake about 20 minutes until the edges start to rise.
For the topping: Combine sour cream, sugar, and vanilla. Spread over warm filling and bake an additional 5 minutes until set. Remove from oven and sprinkle baked crumbs on top. Cool completely, cover, and chill for at least 2 hours.