Decorated with Chocolate Christmas Trees, this Baileys Tiramisu Cake is the perfect cake to serve for this upcoming holiday! Use my cake pan converter to scale the recipe for a different-size cake pan.
Finely chop the dark chocolate into small pieces. Place 3/4 of the chopped chocolate (don't have to be extremely accurate) into a heat-proof mixing bowl and place it over a bowl of simmering water (the bottom of the bowl should not be touching the simmering water). Stir the chocolate with a spatula frequently until all the chocolate has melted.
Immediately after the chocolate has melted, remove the bowl from the pot of simmering water. Stir in the remaining 1/4 chopped chocolate until the chocolate has melted. Set aside to cool slightly until the chocolate has thickened but still liquid enough to pipe.
Line a baking sheet with parchment paper. Transfer the chocolate into a piping bag. Snip off the tip and pipe chocolate trees in different sizes on the parchment paper. (You will end up with more trees than required but they can be used to decorate other cakes).
Let the chocolate set completely at room temperature (do not harden the chocolate in the refrigerator), preferably overnight.
Peel the Chocolate Trees carefully off the parchment paper and store in an airtight container until needed.
Chill a bowl (preferably metal) in the refrigerator for 15 minutes. Pour cream into the bowl and whip with an electric mixer (gradually increasing the speed) until stiff peaks formed. Place the cream in the refrigerator to keep it chilled.
If you want to whip the cream manually with a whisk, place the bowl of cream over a bigger bowl of ice cubes and a little water (the bowl of cream should be touching the ice cubes) so that the cream stays cold as you whip.
Brew about 150 ml of espresso (if you want to use instant coffee, make a double strength coffee - i.e., double the amount of instant coffee as recommended to make 150 ml of coffee). Transfer the espresso into a shallow bowl.
Stir in the sugar while the espresso is hot to dissolve it then set aside to cool completely to room temperature. Stir in the Baileys. Set aside.
Place Baileys in a small heat-proof bowl and sprinkle gelatin on top. Set aside for 5 minutes.
Place the bowl of Baileys Gelatin in a pan of simmering water and heat up until the gelatin has dissolved. Remove from heat and set aside to cool to room temperature.
While the Baileys Gelatin is cooling, place egg yolks and caster sugar in a large heat-proof mixing bowl and whisk with a wire whisk immediately.
Place the mixing bowl over a pot of simmering water (the bottom of the bowl should not be touching the simmering water) and whisk constantly until the mixture has thickened and can form a ribbon shape when dripped from the wire whisk.
Remove the mixing bowl from heat and continue whisking until the mixture has cooled down to room temperature.
Note: Make sure the Baileys Gelatin, zabaglione and mascarpone cheese are at room temperature before proceeding with this step. If the Baileys Gelatin has hardened, heat it up again until it is liquid but not hot.
Whisk the Baileys Gelatin into the zabaglione until incorporated. Add the mascarpone cheese into the zabaglione and whisk until the mascarpone cheese has been incorporated.
Take out the whipped cream that has been chilling in the refrigerator and add 1/3 of the whipped cream into the zabaglione-mascarpone mixture. Whisk gently to incorporate the whipped cream. Fold in the rest of the whipped cream in 2 batches, either with a wire whisk or a rubber spatula, making sure the whipped cream is fully incorporated. Use the Tiramisu Cream immediately.
Wrap a large plastic wrap (big enough to wrap up the cake later) over a cake board and place a 7-inch (3-inch tall) cake ring in the middle of the cake board. Dip the savoiardi biscuits for 2 seconds on each side into the Espresso and place it on the bottom of the cake ring. (If using sponge cake, brush 1/3 of the Espresso onto the sponge cake.)
Pour 1/3 of the Tiramisu Cream onto the savoiardi biscuits (or sponge cake) and spread it out evenly with the back of a spoon. Sieve a thick layer of cocoa powder over the Tiramisu Cream.
Repeat - a layer of dipped savoiardi, 1/2 of the remaining Tiramisu Cream, dusting of cocoa powder, one last layer of dipped savoiardi, remaining Tiramisu Cream.
Wrap up the cake with the plastic wrap and chill in the refrigerator overnight.
The Next Day
Chill a bowl (preferably metal) in the refrigerator for 15 minutes. Pour cream into the bowl, add in sugar and vanilla and, whip with an electric mixer (gradually increasing the speed) until stiff peaks formed. Place the cream in the refrigerator to keep it chilled.
Unwrap the Tiramisu Cake and very carefully transfer it to a clean cake board. Wipe the exterior of the cake ring with a hot tea towel and slowly unmould the cake. If it's hard to unmould, run a thin skewer / small spatula along the sides of the cake to ease the removal of the cake ring.
Freeze the cake for 15 to 30 minutes so that it's easier to decorate the cake.
Spread the chilled vanilla whipped cream thinly all over the cake (top and sides). Use a paper towel to clean the edges of the cake board if needed. Chill the cake in the refrigerator for another 15 to 30 minutes or until ready to serve.
Use a small spoon to spread melted chocolate onto the "trunks" of the Chocolate Trees and stick the trees onto the whipped cream. Serve immediately or within 1 hour.
Note: You can also stick the Chocolate Trees onto the cake and chill the cake until ready to serve - but serve immediately as water will condense on the cold chocolate.
To make a clean slice, dip a knife in hot water and wipe dry with a paper towel. Slice the cake then repeat the dipping and drying for each slice.