Coffee base

1. Pour the cooled coffee into a shallow bowl or pie plate and mix with 2 tbsp of sugar. Stir in the Marsala or rum, if using, and set the baking dish nearby.
2. Separate the eggs, placing the yolks in one large bowl and the whites in another clean bowl.

Mascarpone filling

1. Beat the egg yolks and sugar with a hand mixer on medium-high speed for 3 to 4 minutes, until the mixture looks pale, thick, and softly ribboned.
2. Add the mascarpone and mix on low speed just until smooth and fully combined. Stop as soon as the mixture looks creamy and even.
3. In the second bowl, beat the egg whites to medium-stiff peaks. When you lift the beaters, the peaks should stand up with a gentle curl at the tip.
4. Fold the egg whites into the mascarpone mixture in 3 additions, using a spatula and a light hand, until no large white streaks remain.

Assemble and chill

1. Dip half of the ladyfingers into the coffee one at a time, about 1 second per side, then arrange them in a snug single layer in the dish. Break a few as needed to fill gaps.
2. Spread half of the mascarpone filling evenly over the ladyfingers, then dust with 1 tbsp / 5 g of the cocoa powder.
3. Repeat with the remaining dipped ladyfingers and the remaining mascarpone filling. Cover and chill for at least 6 hours, or overnight for a more settled texture.
4. Just before serving, dust the top with the remaining 1 tbsp / 5 g cocoa powder. Success looks like soft, distinct layers that hold their shape when spooned or sliced, with tender biscuits and a cream that feels plush rather than runny.
5. (Optional) Upgrade: Mix a little very finely grated dark chocolate into the final cocoa dusting. It gives the top a deeper bittersweet finish and makes the coffee flavor feel a little more dramatic without changing the dessert’s classic feel.