Preheat oven to 350 F.
In large mixing bowl, combine flours, brown sugar and cut in the butter using a pastry blender.
Once crumbly, add the crust mixture to a greased 9x13-inch baking dish. Press into the bottom with a measuring cup. (Will appear loose and that's OK!)
In same mixing bowl, whisk pumpkin, milk, eggs and pumpkin pie spice. Pour over the crust and spread out over the crust.
Bake at 350 F for 20 minutes.
Meanwhile, in small mixing bowl, toss together the chopped pecans, brown sugar and cinnamon. After 20 minutes, remove the baking dish and top with the pecan mixture. Continue baking at 350 for another 15-20 minutes, or until toothpick comes out clean in the center.
Let cool on cooling rack and cut into 2 inch x 2 inch squares.
Top each Pumpkin Pecan Bar with dollop of whipped cream.