Heat oven to 350 degrees. Line a 9 by 13 pan with parchment paper allowing it to extend over sides.

Mix flour, 1/4 cup sugar, and brown sugar in a large bowl. Using your fingers rub butter into mixture until it resembles course crumbs. Stir in oats and nuts.

Reserve one cup of this mixture and press the remainder into the bottom of prepared pan. Bake for 14 minutes.

Meanwhile, in the bowl of electric mixer beat cream cheese, pumpkin, eggs, remaining sugar and pumpkin pie spice until well blended and smooth.

Pour over baked crust.

Sprinkle the reserved crumb mixture over the pumpkin and press down very lightly.

Bake for 25 minutes.

Cool for 10 minutes in pan before lifting out to cooling rack to cool completely.