Preheat the oven to 325 degrees F, lightly mist the sides of a 10-inch by 15-inch jelly roll pan with non-stick spray, and line it with parchment, allowing a little of the parchment to overhang on one of the short sides.

Place the eggs and sugar in a large mixing bowl and whip on high speed for a full 5 minutes (minimum), until very pale and tripled in volume.

Place the flour, cinnamon, baking powder, salt, nutmeg, and ginger in a medium bowl and whisk to combine.

Place the pumpkin, sour cream, melted butter, milk, and vanilla in a medium bowl and whisk to combine.

When the egg/sugar mixture is very pale and tripled in volume, gently fold in the flour mixture.

Gently fold in the pumpkin mixture, and transfer the batter to the prepared pan, smoothing it out into an even layer.

Bake for 22 to 28 minutes, or until set.

While the cake is still hot, dust it generously with powdered sugar, then lay a clean kitchen towel on top.

Starting at the short side with the parchment overhang, carefully roll the cake and the towel together into a tight cylinder, cinnamon-roll style.

Allow the cake to cool completely, then unroll and spread the filling on in an even layer.

Re-roll the cake and filling together and chill in the refrigerator until set.

Dust with powdered sugar for garnish, slice, and serve.

Place the cream cheese and powdered sugar in a large mixing bowl and beat together until smooth (about 1 minute on medium speed).

Whisk in the cream on medium speed, a little at a time, stopping frequently to scrape the bottom and sides of the bowl with a silicone spatula.

When all the cream has been added, scrape the bottom and sides of the bowl with a silicone spatula, then whip in the lemon juice and vanilla extract until the mixture looks fluffy and can hold stiff peaks (about 1 minute on high speed).