Heat oven to 375°F. Grease a 10x15-inch jelly roll pan with nonstick spray. Line it with parchment paper, letting the paper hang over the long sides by about an inch to create handles for lifting the cake out. Lightly coat the parchment with cooking spray as well and set aside.
Whisk the dry ingredients together in a medium bowl.
Using the high speed of an electric mixer or with a hand mixer in a large bowl, beat the eggs until slightly thickened and frothy, about 3 minutes.
On low speed, mix in the sugar and pumpkin until just combined. Then, use a rubber spatula to gently fold in the dry ingredients until no streaks remain.
Pour the batter into the prepared pan and spread into an even layer and drop the pan on the counter a few times to even and eliminate air bubbles.
Bake until the top springs back when lightly touched, about 12 - 15 minutes.
Meanwhile, dust a clean, thin kitchen towel with powdered sugar and set aside. Or once done baking you can use my new favourite easy (and less messy) method, roll the cake right in the parchment from the pan.
If using a towel, loosen the edges of the cake, turn it upside down (invert) onto the prepared tea towel, and carefully peel off the parchment paper. If rolling in parchment, skip inverting and roll the cake up directly in the paper.
Slowly, tightly, roll the cake in the towel or parchment paper, working from short end to short end.
Transfer the wrapped cake roll to a wire rack to cool until it reaches room temperature - about 2 to 3 hours.