Ingredients
200g powdered sugar
120g unsalted butter, at room temperature
30ml coffee-flavored liqueur
22g unsweetened cocoa powder
1 pinch salt
80g mascarpone cheese
30g melted butter
50g unsweetened cocoa powder
15g all-purpose flour
3g kosher salt
5 large eggs, at room temperature
160g white sugar
2.5g vanilla extract
2 tbsp powdered sugar, as needed
240ml heavy cream, boiling-hot
225g dark chocolate chips
Directions
Step 1
In a stand mixer bowl with a whisk attachment, whip together powdered sugar, butter, coffee-flavored liqueur, cocoa powder, and salt on high speed until fluffy.
Step 2
Transfer the filling to a separate bowl and mix in the mascarpone cheese until combined. Set aside and clean the stand mixer bowl.
Step 3
Preheat the oven to 200°C (400°F).
Step 4
Prepare a 33x46cm rimmed sheet pan for the sponge cake. Brush the pan with some melted butter, line it with parchment paper, and brush the remaining melted butter on top.
Step 5
In a bowl, whisk together cocoa powder, flour, and salt, ensuring there are no clumps.
Step 6
In the clean stand mixer bowl, beat the eggs and sugar with the whisk attachment until fluffy, thick, and very light in color (about 2-3 minutes).
Step 7
Add the vanilla and half of the cocoa powder mixture. Mix on low speed for a few seconds, then add the remaining cocoa mixture and mix on low for a few more seconds. Switch to high speed and mix until moistened but not fully blended.
Step 8
Remove the whisk attachment and hand-whisk the batter until evenly blended.
Step 9
Pour the batter onto the prepared sheet pan, spread it out with a spatula, and tap the pan on the counter to remove air bubbles.
Step 10
Bake in the preheated oven until the top is dry and the edges start to pull away from the sides (8-10 minutes).
Step 11
While the cake is baking, sift powdered sugar onto a clean kitchen towel, covering an area slightly larger than the sponge cake.
Step 12
Remove the cake from the oven, run a knife around the edges of the pan, and dust some powdered sugar over the top. Run a spatula under the parchment paper to ensure it's not stuck to the pan.
Step 13
Quickly flip the pan onto the sugared area on the towel to invert the cake. Carefully remove the parchment paper, sift more powdered sugar over the cake, and gently roll the cake up inside the towel. Allow it to cool for 15 minutes.
Step 14
Carefully unroll the cooled cake, spread the buttercream filling on top, and roll the cake up using the towel to lift it if needed.
Step 15
Sprinkle more powdered sugar on top, wrap the log in plastic wrap, and refrigerate until firm (about 2 hours).
Step 16
To make the ganache frosting, pour the hot cream over the chocolate chips in a bowl, let it sit for 1 minute, then whisk until the chocolate is melted.
Step 17
Make an angled cut 7.5cm from one end of the log. Place the log on a parchment-lined sheet pan.
Step 18
Apply some filling to the angled slice and attach it to one side of the log. Spread a layer of ganache all over the cake, except for the swirls on the ends, and refrigerate for 15 minutes to firm up the ganache.
Step 19
Use the tip of a knife to carve lines into the ganache to create the appearance of tree bark. Refrigerate until completely chilled.
Step 20
Dust with cocoa powder and powdered sugar before serving.