Preparation Steps

• In a heatproof bowl set over a saucepan of simmering water (double boiler), whisk together the egg yolks and granulated sugar. Continue whisking until the mixture is pale yellow and thickened, about 5-7 minutes. Remove from heat and let cool slightly.
• In a separate large bowl, beat the mascarpone cheese until smooth. Gently fold in the cooled egg yolk mixture until just combined.
• In another bowl, whip the cold heavy cream until stiff peaks form. Gently fold the whipped cream into the mascarpone mixture until evenly incorporated.
• In a shallow dish, combine the cooled espresso and coffee liqueur (if using).
• Quickly dip each ladyfinger into the espresso mixture, ensuring they are soaked but not soggy. Arrange a single layer of soaked ladyfingers in the bottom of an 8x8 inch baking dish.
• Spread half of the mascarpone cream mixture evenly over the ladyfingers.
• Repeat with another layer of soaked ladyfingers, followed by the remaining mascarpone cream mixture.
• Cover the dish with plastic wrap and refrigerate for at least 4 hours, or preferably overnight, to allow the flavors to meld and the tiramisu to set.
• Just before serving, dust the top of the tiramisu evenly with unsweetened cocoa powder.