Step 1

Preheat oven to 350° degrees F. Liberally grease a 13x9" rectangular light metal baking pan with cooking spray; set aside.

Step 2

In a large bowl, combine the flour, granulated sugar, brown sugar, baking powder, baking soda, salt, and 3 teaspoons of the pumpkin pie spice, stirring together. Add in the vegetable oil and stir to combine until mixture becomes moistened and crumby. Reserve 2 heaping cups of crumbs aside in a separate bowl.

Step 3

To the original bowl, add in the pumpkin puree, buttermilk, lightly beaten egg, remaining 1 teaspoon pumpkin pie spice and vanilla extract and stir until just barely combined; some lumps in the batter is okay.

Step 4

Pour the pumpkin cake batter into the prepared baking pan. Evenly sprinkle handfuls of the reserved crumb mixture over the pumpkin batter until completely and evenly coated with crumb.

Step 5

Bake for 30-35 minutes or until a toothpick inserted near the center comes out clean. After baking, prepare your glaze by whisking together the confectioners' sugar, pumpkin spice coffee creamer and vanilla extract in a medium bowl. Drizzle the glaze over the warm cake. Let stand for 15 minutes before cutting into squares.