To Make the Cake Layers:

1. Preheat the oven to 350°F (176°C). Line the bottom of three 8-inch (20cm) cake pans with parchment paper and grease the sides.
2. In a large mixing bowl, cream the butter and sugar on medium speed until light in color and fluffy, 3-4 minutes.
3. Add the vanilla extract and vegetable oil and mix until combined.
4. Add eggs and egg white in two batches, mixing until incorporated after each addition. Scrape down the sides of the bowl as needed to make sure everything is combined.
5. Add the dry ingredients to a medium sized bowl and whisk to combine.
6. Add half of the flour mixture to the batter and mix until combined. Add the pumpkin puree to the batter and mix until combined. Add the remaining flour mixture and mix until well combined and smooth. Scrape down the sides of the bowl as needed to ensure everything is well combined. The batter will be thick.
7. Divide the batter evenly between the prepared cake pans.
8. Bake for 20-25 minutes, or until a toothpick inserted in the middle comes out with a few crumbs.
9. Remove cakes from the oven and allow to cool for 3-4 minutes, then remove from pans to a cooling rack to finish cooling.

To Make the Tiramisu Filling:

1. Combine the egg yolks and sugar in the top of a double boiler. If you don’t have a double boiler, you can use a mixing bowl set over a pot with simmering water in it. I use my mixer bowl. Do not let the water boil, or it will be too hot. To ensure that the steam cooking the eggs doesn’t get too hot, occasionally lift the bowl to release the steam.
2. Cook for about 7-10 minutes whisking constantly with heat on low, until mixture is light in color and sugar is dissolved. The temperature of the mixture should reach about 155°F (68°C). If mixture starts to get too thick and a darker yellow, it’s overcooked.
3. When done, whip egg yolks with a mixer until they thicken and lighten a bit to a pale yellow.
4. Add the mascarpone cheese to a medium sized bowl, then add about 1/3 of the yolks to the mascarpone cheese and carefully fold them together. Add the remaining egg yolks and gently fold into the cheese mixture until combined, being careful not to deflate the yolks or over mix the mascarpone cheese. When mascarpone cheese is over mixed, it can start to separate.
5. Add the heavy whipping cream for the filling to another mixer bowl and whip on high speed until stiff peaks form, about 5 minutes.
6. Carefully fold the whipped cream into mascarpone mixture by first folding about 1/3 of the whipped cream into the mascarpone mixture. Carefully fold the remaining whipped cream into the mascarpone mixture. Set mixture in the fridge until ready to use.

To Make the Frosting:

1. Combine the mascarpone cheese, powdered sugar and kahlua and mix on low speed until combined and smooth. Do not over mix the mascarpone cheese. When mascarpone cheese is over mixed, it can start to separate. Set frosting in the fridge until ready to use.

To Build the Cake:

1. Remove the domes from the tops of the cakes with a large serrated knife.
2. Combine the ingredients for the espresso mixture.
3. Place the first cake layer on a serving place or cardboard cake circle.
4. Drizzle 4-5 tablespoons of espresso mixture over the cake layer.
5. Pipe a dam around with outside of the cake with the mascarpone frosting.
6. Fill in the center of the dam with about 1/3 of the tiramisu filling, then spread into an even layer.
7. Top the filling with the second layer of cake, then repeat steps 4-6.
8. Top the cake with the final layer of cake, then drizzle another 4-5 tablespoons on top of the cake layer.
9. Add a crumb coat to the sides of the cake with the mascarpone frosting, then full frost the outside of the cake, leaving the top bare.
10. Pipe a border around the top edge of the cake with the remaining frosting.
11. Fill in the border with the remaining 1/3 of the tiramisu filling.
12. Sprinkle a little cocoa onto the top of the cake, if desired, then press the cookie sticks onto the sides. The cake should be refrigerated until ready to be served. Cake is best for 3-4 days.