Reserve ½ cup dry cake mix. In a large bowl, combine remaining cake mix, ¼ cup of oil and 1 egg; Beat until crumbly. Stir in nuts. Press firmly on the bottom of 13"x9" pan.
In the same bowl combine remaining ingredients (Not including the oatmeal streusel) and mix well. Pour over prepared crust. Place the 13"x9" pan on a cookie sheet (to prevent excessive browning on the bottom) then place and in a 350°F pre heated oven for 15 min.
To prepare streusel combine all dry ingredients and cut in butter until the mixture is crumbly.
After the first bake time of 15 minutes has elapsed remove the 13"x9" pan from the oven and spread the streusel topping evenly over the top of the pumpkin bar.
Place back in the oven on the cookie sheet to prevent the bottom from getting to dark.
Bake your pumpkin oatmeal streusel bar until set and the top is golden.