Step 1: Prepare the Whipped Cream

• Chill a mixing bowl and whisk attachment in the fridge for 10–15 minutes.
• Pour heavy whipping cream into the cold bowl and whip until stiff peaks form.
• Cover and refrigerate until needed.

Step 2: Make the Custard

• Combine egg yolks and sugar in the top of a double boiler over simmering water.
• Reduce heat to low and cook, stirring constantly, for about 10 minutes until smooth and slightly thickened.
• Remove from heat and transfer to a mixing bowl. Whip until thick and lighter in color.
• Beat in mascarpone on medium-high speed until smooth and fully combined.

Step 3: Fold in the Whipped Cream

• Gently fold the chilled whipped cream into the custard mixture with a spatula, keeping the mixture light and airy.
• Set aside while assembling the tiramisu.

Step 4: Assemble the Tiramisu

• Line the bottom and sides of a springform pan or large glass bowl with ladyfingers.
• Lightly brush the bottom layer with coffee or coffee liqueur, avoiding oversaturating. (Do not brush the outside edge ladyfingers in a springform pan.)
• Spread ⅓ of the custard evenly over the ladyfingers.
• Dunk the next layer of ladyfingers quickly in coffee or coffee liqueur and place on top of the custard, staggering gaps as needed.
• Cover with another ⅓ of custard, then repeat with the final layer of coffee-dipped ladyfingers.
• Top with the remaining custard and smooth the surface.

Step 5: Garnish and Chill

• Dust the top with cocoa powder and decorate with chocolate curls.
• Refrigerate for at least 4 hours or overnight before slicing and serving.