Method

• 1.
  Place 1 cup (250ml) espresso and 150g caster sugar in a small saucepan over low heat, stirring to dissolve sugar. Remove from heat. Add 1 cup (250ml) chilled espresso to the syrup. Set aside.

• 2.
  Place eggs and 150g sugar in a large heatproof bowl set over a saucepan of gently simmering water (don’t let base of bowl touch the water). Using a hand whisk, whisk for 6-8 minutes, until sugar has dissolved and mixture reaches 60°C on a kitchen thermometer (when you lift the whisk and mixture drops back into the bowl, it should hold its shape for a brief moment). Transfer to a stand mixer fitted with the whisk attachment and whisk on high speed until completely cooled, pale and fluffy. Whisk in cream and vanilla on high speed for about 5 minutes, or until stiff peaks form. Turn off mixer. Add mascarpone and 1/2 cup (125ml) coffee syrup. Whisk on low speed until combined and thick.
• 3.
  Add vodka and coffee liqueur to remaining coffee syrup. Dip half the savoiardi biscuits into the syrup and use to line the base of a 4L-capacity serving dish. Spread half the cream mixture over the top. Repeat layering with remaining biscuits, coffee syrup and cream mixture. Use an offset spatula to create peaks. Chill overnight until firm and set.
• 4.
  Place remaining 100ml coffee and remaining 1 cup (220g) sugar in a saucepan over medium heat, stirring to dissolve sugar. Bring to a simmer and reduce heat to low. Cook, stirring constantly, for 6-8 minutes, until thickened. Transfer to a bowl and cool, stirring occasionally so it doesn’t set.
• 5.
  Pour cooled syrup over tiramisu and dust with cocoa to serve.