Mix all batter ingredients together until smooth. I just use my whisk and whip it well.
Pour onto a parchment paper lined jelly roll pan. I grease my parchment paper before pouring the batter into it.
Bake at 350℉ for 10-15 minutes until the roll is firm to the touch. It will be thin and won't take long to bake. While it bakes, whip all filling ingredients together until light and fluffy.
Prepare a kitchen towel by sprinkling it with powdered sugar. When the pumpkin roll is done baking, flip it onto the dish towel and remove the parchment paper, then sprinkle that side with powdered sugar too. Roll up the pumpkin roll with the dish towel, and put it into the refrigerator to cool. This 'trains' the pumpkin roll into the shape that you'll want it to keep.
After it has cooled for 4-6 hours unroll it, spread it with the filling and roll it up again, this time without the dish towel.
Now for the biggest tip of all...wrap it up in tin foil and put it into the freezer before slicing it. After 12 hours, you can slice it perfectly. It never freezes completely solid but hard enough to make slicing a breeze. After it's sliced, I put mine back into the freezer and remove 20-30 minutes before serving.