Mix all dry ingredients in a bowl. Set aside.
Beat eggs in mixer for 3 minutes. Stream in oil.
Add pumpkin puree, followed by vanilla.
Whisk dry ingedients to make sure all in evenly incorporated.
Add the dry ingredient to the wet ingredients
Mix just until incorporated on low. Don't over mix.
microwave 1 teaspoon of batter to see if it's flavored enough. Not all pumpkin spice are equal and you may need to add more.
Pour batter into sheet pan. Smooth out with offset spatula.
Bake for 15 to 20 minutes until a thermometer measures at least 205 degrees F. Check at 15 minutes. You may need to cover with foil at this point, if edges are browning. Continue to bake until you reach at 205 F.
Allow to cool completely before applying whipped cream.