Prepare the coffee mixture by brewing strong coffee and mixing it with Bailey’s Irish Cream.
Whisk together the egg yolks and sugar in a bowl and cook them over a double boiler.
Once the egg mixture is thick and pale, remove it from heat and fold in the mascarpone until smooth.
In a separate bowl, whip the heavy cream until soft peaks form, then gently fold it into the mascarpone mixture.
Dip the ladyfingers briefly into the coffee mixture, then layer them in a rectangular dish.
Spread half of the mascarpone mixture over the layer of ladyfingers.
Add another layer of dipped ladyfingers followed by the remaining mascarpone mixture.
Cover and refrigerate the tiramisu for at least 4 hours, preferably overnight.
Before serving, dust the top with cocoa powder for a finishing touch.