Preheat the oven to 375℉. Lightly grease and flour a 10"x15" jelly roll pan with vegetable shortening and line it with parchment paper that is about an inch or two longer on the two short sides (This is optional but will give you something to grab onto as you lift out the baked cake.)
Dry Mixture: Combine the flour, salt, spices, baking powder, and baking soda in a medium sized bowl. Whisk until well combined and set aside.
Wet mixture: combine the eggs, vanilla extract, and granulated sugar in a large bowl. Mix on medium speed for 1-2 minutes until lightened in color. (If you prefer a whisk, you can use that. We used a hand mixer.)
Add the canned pumpkin to the wet mixture and mix with hand mixer (or whisk) once again until smooth.
Stir the dry mixture into the wet mixture, mixing with your spatula or large spoon just until combined and smooth.
Carefully pour the pumpkin batter into your prepared jelly roll pan or baking sheet and use a spatula or back of a spoon to spread it out evenly. Bake for 13-15 minutes. The cake is done when it springs back when lightly touched, or when a toothpick can be inserted and comes out clean (or with just a few crumbs attached.)
Dust a clean baking towel (that is longer and wider than the cake) liberally with powdered sugar as the cake is baking. This is going to prevent the baked cake from sticking to it.
When the cake has finished baking lift it out of the pan and flip it onto the sugared towel.
Peel back the parchment paper. Roll up the cake in the towel tightly. Then place the rolled cake on a wire rack to cool completely. If working in advance, you can wrap it in plastic wrap and refrigerate overnight.