Preheat oven to 350°F and line a 10x15 jelly roll pan (baking sheet with sides) with parchment paper. Leave a little extra parchment paper on the sides so that it is easier to lift the cake after baking In a small mixing bowl, whisk together flour, cornstarch, pumpkin pie seasoning, baking powder and salt.
In a separate medium mixing bowl, whisk together eggs and sugar until well combined. Mix in vanilla and fresh finely grated carrots. Add in the dry mixture and mix with a rubber spatula until combined.
Spread evenly across jelly pan and bake for 12-14 minutes.
Lay a clean dish/tea towel on the counter and carefully flip cake onto it (with the cake on the towel and the parchment paper on top). Slowly peel the parchment paper off the cake. Roll the cake up into a long log (photo above) and place on a cooling rack. Let cool completely, about 30 minutes.
While the cake is cooling, make the cream cheese filling. Cream together butter and cream cheese, then add in powdered sugar (1/2 cup at a time) and vanilla extract. Mix until smooth.
Once the cake has cooled, slowly unroll it. Spread the cream cheese filling evenly across the cake, leaving a little room around the sides.
Carefully re-roll the cake, peeling away the towel as you roll. Wrap the roll in cling wrap and refrigerate for at least an hour or freeze for about 30 minutes. Unwrap and slice using a hot knife. Serve & enjoy!