1. Preheat oven to 350 degrees F.
2. In a medium bowl, combine flour, baking soda, cinnamon, and nutmeg and stir until evenly distributed. Set aside.
3. In a large bowl, beat together eggs and sugar.
4. Add pumpkin and mix until well combined.
5. Add dry ingredients to the wet and mix until just combined.
6. Grease a 10" x 15" jelly roll pan.
7. Line the pan with parchment paper, and then grease and lightly flour the parchment paper.
8. Pour cake batter over the parchment paper and use a spatula to spread evenly to edges (you do not need do have it all the way to the edges - I usually leave a little space to prevent sticking and help with transfer. You just need to have a generally even rectangular shape).
9. Bake for 15 minutes or until set. (Cake cooks fast so watch carefully to avoid burning the edges! If the edges do get a little dark, you can use kitchen shears to trim them and still easily remove the cake from the parchment paper.)
10. While cake is baking, generously sprinkle powdered sugar over a flour sack towel (or triple-layered paper towels), using a sieve or sifter.
11. Turn hot cake onto the towel. Remove parchment paper. Trim off burnt or crusty edges.
12. Sprinkle more powdered sugar generously over the hot cake and quickly roll up with towel inside.
13. Let cake cool completely, about 30 minutes. (Use this time to prepare the filling.)

For the Filling:

1. Combine cream cheese and butter, and using a hand mixer, whip until fluffy.
2. Add powdered sugar, a little at a time, to avoid a mess.
3. Add vanilla.
4. With a butcher's knife or a grater, shave your chocolate. (I like having some really fine stuff, and some bigger slivers as well).
5. Add chocolate to cream cheese frosting, and use a spoon to incorporate.

Assemble the Cake Roll:

1. Unroll cooled cake and spread the filling mixture on top, leaning heavily towards the end when you will start the roll (the frosting will push forward a little as you go).
2. Roll-up cake long side with filling on the inside. Don't roll the towel with it this time! Wrap cake in parchment or waxed paper and then aluminum foil.
3. Chill in freezer for about 30 minutes until set firm. (You can keep in freezer until time to serve or transfer to the fridge if you like it a little softer.)
4. To serve:
5. Remove roll from packaging and place on your serving platter.
6. Top with a dusting of powdered sugar and left-over chocolate shavings.
7. Cut about 1/2 inch thick slices and enjoy! (It is easiest to cut while still frozen and I also enjoy eating it frozen!)