In a large bowl whisk together the flour, baking powder, baking soda, and spice blend until combined and set aside.
Whisk together the eggs, oil, pumpkin puree, sugars, butter, and vanilla in a separate large bowl until completely mixed.
Pour the wet ingredients into the dry ingredient bowl and mix until combined and smooth.
Pour the batter onto a 10x15 cookie sheet tray that has been lined with parchment paper and sprayed with non-stick spray and spread out until even.
Bake in the oven at 350° for 20-25 minutes or until firm in the center and a toothpick comes out clean after sticking in the center.
Cool the cake completely on a rack, which takes about 45 minutes, you can keep this warm, but the frosting will melt a bit.
Generously frost the cake with the cream cheese frosting, slice, and serve.
Notes
Make-Ahead: You can make this up to 2 days ahead of time.How to Store: Carefully cover and keep in the refrigerator for up to 6 days. Cover and freeze for up to 3 months. It would be better if the cake was not frosted before freezing.I prefer to pull it out of the refrigerator for about an hour before slicing and serving it, so the cream cheese frosting softens up a bit.Feel free to add assorted seasonal toppings like candy corns or other Halloween-themed decorations.You may also add chocolate chips or walnuts into the cake batter for enhanced flavor.