01 - Whisk egg yolks with powdered sugar in a heatproof bowl over simmering water for 2-3 minutes until thick and pale. Remove from heat and let cool slightly.
02 - Beat cold heavy cream in a separate bowl until stiff peaks form.
03 - Fold mascarpone into cooled egg mixture until smooth. Gently fold in whipped cream until fully incorporated.
04 - Combine cooled coffee and coffee liqueur in a shallow dish.
05 - Quickly dip each ladyfinger into coffee mixture for 1-2 seconds per side. Arrange half in single layer in 8-inch square dish.
06 - Spread half the mascarpone mixture evenly over ladyfingers.
07 - Repeat with remaining dipped ladyfingers and mascarpone mixture.
08 - Cover with plastic wrap and refrigerate at least 4 hours or overnight for best results.
09 - Dust generously with cocoa powder and garnish with chocolate shavings if desired before serving.