1
For the mascarpone cream: In a heatproof bowl, whisk together the egg yolks and sugar until pale and thick.
2
Place the bowl over a pan of simmering water (double boiler) and whisk constantly for 5-7 minutes until the mixture is thick and reaches 70°C.
3
Remove from heat and whisk in the mascarpone cheese until smooth and well combined.
4
In a separate bowl, whip the double cream with vanilla extract until soft peaks form.
5
Gently fold the whipped cream into the mascarpone mixture until just combined. Be careful not to overmix.
6
For the coffee soak: Mix the espresso with coffee liqueur (if using) in a shallow dish.
7
Quickly dip each ladyfinger into the coffee mixture (don't soak them too long or they'll become soggy).
8
Arrange half the dipped ladyfingers in a single layer in a 20x30cm serving dish.
9
Spread half the mascarpone cream over the ladyfingers, smoothing the top.
10
Repeat with the remaining ladyfingers and cream, creating a second layer.
11
Cover with cling film and refrigerate for at least 4 hours, preferably overnight.
12
Before serving, dust the top with cocoa powder and sprinkle with grated dark chocolate.