Chocolate Tiramisu Cake

Cake is my downfall.
I can refuse
a glass of wine,
push away
an opened box
of handmade chocolates,
spurn a toffee from the tin
and turn my nose up
at a HobNob,
but I can never,
ever resist
a slice of cake.
-Nigel Slater

I have to agree with Mr. Slater; it’s hard to say no to a good piece of cake. I recently received Tessa Huff’s (Style Sweet CA) new cookbook Layered, which is packed full of every kind of layer cake you can imagine, plus baking and decorating tips and techniques. It’s beautifully photographed, with both classic and inventive cake recipes. I mixed and matched two recipes from Tessa’s book to come up with this Chocolate Tiramisu Cake, but next on my list are the Lemony Carrot Cake, Riesling Rhubarb Crisp Cake, and Banana Cream Cake.

Chocolate Tiramisu Cake

Adapted from Layered by Tessa Huff

A few notes: I made this into a ‘mini’ cake, and used three 6-inch cake pans (the leftover batter I baked into cupcakes). I didn’t have instant espresso powder for the rum-espresso soak, so instead I used 1/4 cup of fresh brewed coffee in place of the 1/4 cup water, and boiled the coffee with the sugar.

Cake
2½ cups (315g) all-purpose flour
1 cup (95g) unsweetened cocoa powder
2½ tsp baking powder
¾ tsp baking soda
1 tsp salt
1/2 cup plus 2 tablespoons (150ml) grapeseed oil (canola oil will work, too)
2 cups (400g) granulated sugar
2 eggs + 1 egg yolk
2 tsp pure vanilla extract
1½ cups (375ml) whole milk
1 cup (250ml) hot strong-brewed coffee (boiled water will work, too)

Rum-Espresso Soak
1/2 cup (100g) granulated sugar
2 teaspoons instant espresso powder
1/4 cup (60ml) dark rum

Mascarpone Buttercream
1/2 cup plus 2 tablespoons (150ml) large egg whites (about 5 large egg whites)
1 1/4 cups (250g) granulated sugar
1 1/2 cups (3 sticks/340g) unsalted butter, at room temperature, cubed
3/4 cup (180ml) mascarpone, softenend
1 tablespoon dark rum
1 teaspoon pure vanilla extract

For the cake
Grease and flour two 8-inch (20-cm) cake pans. Preheat the oven to 350F.

In a medium bowl, whisk together the flour cocoa, baking powder, baking soda, and salt.

In the bowl a stand mixer fitted with a paddle, beat together the oil and sugar on medium for 2 minutes. Add the eggs, yolk, and vanilla and beat on low until combined.  Stop the mixer and scrape down the bowl.

Turn the mixer to low and add the flour mixture in three batches, alternating with the milk, beginning and ending with the flour mixture. Scrape down the bowl as needed. With the mixer on low, stream in the coffee. Mix on medium-low until combined, about 30 seconds.

Divide the batter between the prepared pans and bake for 25-28 minutes, or until a skewer inserted in the center of the cake comes out clean.

Leave the cakes to cool on a wire rack for 10-15 minutes, then turn out onto a wire rack to cool completely.

For the rum-espresso soak
While the cakes are cooling in their pans, combine the sugar, espresso powder, and 1/4 cup (60ml) water in a saucepan. Bring them to a boil, then reduce the heat to low and simmer for about 5 minutes. Remove the pan from the heat and stir in the rum. Let the liquid cool slightly before use, about 5 minutes.

For the mascarpone buttercream
Place the egg whites and sugar in the bowl of a stand mixer. Whisk them together by hand to combine. Fill a medium saucepan with a few inches of water and place it over medium-high heat. Place the mixer bowl on top of the saucepan to create a double boiler. The bottom of the bowl should not touch the water.

Whisking intermittently, heat the egg mixture until it registers 160F (70C) on a candy thermometer or is hot to the touch. Once hot, carefully fit the mixer bowl onto the stand mixer.

With the whisk attachment, beat the egg mixture on high speed for 8 to 10 minutes, until it holds medium-stiff peaks. When done, the outside of the mixer bowl should return to room temperature and no residual heat should be escaping from the meringue. Stop the mixer and swap out the whisk attachment for the paddle. With the mixer on low speed, add the butter, a few cubes at a time. Once incorporated, turn the mixer to medium-high and beat until the buttercream is silky smooth, 3-5 minutes. Reduce the speed to medium-low and add in the mascarpone, rum, and vanilla. Mix until combined.

To assemble the cake
Brush each of the cooled cakes with the rum-espresso soak (you may want to put a piece of parchment paper under the wire rack to catch any drips). Put a layer on a turntable or serving dish top side up, and spread 1/2 cup (120ml) of the buttercream with an offset spatula. Top with the next layer of cake (top side down) and frost the cake with the remaining buttercream. Finish with a blanket of chocolate curls, if desired.

Gold-rimmed plate and gold flatware are from Canvas Home Store.