Method

• 1.
  In a stand mixer fitted with the whisk attachment, whisk egg yolks and 75g sugar until pale and fluffy. Slowly whisk in mascarpone, Strega and sambuca until just combined. Transfer to a large bowl.

• 2.
  Combine 1/2 cup (125ml) water and remaining 500g sugar in a saucepan over medium-high heat. Cook, stirring constantly, until sugar is dissolved. Bring to the boil and cook, without stirring, until 114°C on a sugar thermometer (this should take about 5 minutes).
• 3.
  Meanwhile, in the cleaned stand mixer, whisk eggwhites to soft peaks. With the motor running, add sugar syrup in a slow, steady stream until combined. Continue whisking for 15-20 minutes or until egg white mixture has completely cooled. Fold meringue into mascarpone mixture.
• 4.
  Place espresso in a heatproof bowl and stand to cool if hot. In batches, dip one-third savoiardi in espresso, gently press out excess and line base of a large 2L (8-cup) bowl. Top with one-third mascarpone mixture and scatter with half each dark chocolate and ground coffee. Repeat layering process, finishing with the final one-third mascarpone. Dust with cocoa powder, then chill for 3 hours to set slightly and for flavours to develop.