Preheat oven to 350°F. For the Topping, mix flour, sugar and pumpkin pie spice in medium bowl. Add butter; toss with spatula until large crumbs form. Stir in pecans. Set aside.
For the Cake, beat cake mix, pumpkin, eggs, butter, pumpkin pie spice and vanilla in large bowl with electric mixer on medium speed about 1 minute or just until mixed.
Spread 1/2 of the batter in greased and floured 9-inch square baking pan. Sprinkle with 1/4 cup of the Topping. Pour remaining batter over top. Sprinkle with remaining Topping.
Bake 35 to 40 minutes or until cake pulls away from sides of pan. Cool in pan on wire rack.