Pumpkin Tiramisu

Espresso Mixture:

1. Combine espresso and rum in a shallow bowl. Set aside.

Pumpkin Mascarpone Whipped Cream:

1. Raw egg option: Add egg yolks and ¼ cup sugar to a medium-sized mixing bowl. Use an electric mixer on medium speed to beat until the eggs are fluffy and pale yellow. When the eggs have tripled in size, you're done.Cooked egg option (Zabaglione): Fill a medium-sized pan with about an inch of water, and bring it to a simmer.  (Or use a double boiler.)Add egg yolks and ¼ cup sugar to a to a medium-sized heatproof bowl (such as Pyrex or metal), and set it on top of the pan with simmering water.Right away, use an electric hand mixer, whisk eggs at a medium speed, and continue beating until the mixture is light and fluffy. When the eggs have doubled in size, you're done. Remove eggs from heat and set aside.Make sure not to leave the eggs on the heat for longer than needed. You only want to heat them, not scramble them.
2. In a separate large mixing bowl, add the cream and remaining ¼ cup sugar. Use an electric mixer on high to whip the cream until soft peaks form.Add the mascarpone and pumpkin, and continue mixing until the mixture is soft and spreadable.Use a rubber spatula to gently fold the egg mixture into the pumpkin mascarpone whipped cream.

Assemble the Tiramisu:

1. Use a small mesh sieve (or a metal tea ball) to dust a 2-quart baking dish (such as an 8"x8" pan) with half the cocoa powder.
2. One by one, dip the ladyfinger cookies into the espresso mixture and then arrange in the baking dish. Make sure the cookies absorb a little of the espresso, but don't leave them in the liquid very long or they'll fall apart.Continue adding cookies until you've got a single layer of cookies, breaking cookies into smaller pieces to fill in gaps as needed.
3. Spread half the mascarpone whipped cream over the ladyfingers. Repeat process, topping mascarpone with another layer of soaked ladyfingers, and finishing with a final layer of the mascarpone mixture. Dust the top with the remaining cocoa powder.
4. Refrigerate at least 4 hours (or overnight). Serve cold with optional berries if desired.Make Ahead / Leftovers:Tiramisu can be stored for 3-4 days in the fridge. Note that the ladyfinger cookies will soften as the dessert sits.