Heat oven to 325. In a small bowl combine oil,  1/4 cup parve whipped topping, and brown sugar until combined. Pour into two 9 inch round pans and sprinkle with pecans.

In a large bowl beat cake mix, pumpkin, water, oil, eggs, and one teaspoon pumpkin pie spice until thoroughly blended. Carefully spoon over pecans in the baking pans.

Bake for approximately 40 minutes or until the cake springs back when touched lightly in the center. Cool for five minutes, then move to cooking rack to cook completely.

Whip remaining whipped topping with powdered sugar, vanilla, and pumpkin pie spice. The mixture will be thicker than plain whipped topping.

Carefully invert one cake onto a serving plate and spread with the whipped cream mixture. Invert second cake onto whipped topping layer and spread with remaining whipped topping mixture.

Make a ring of whole pecans around the top of the cake if desired for garnish.

Source: Betty Crocker Fall Baking, the original recipe can be found here.