Bring 100 g of sugar and 100 g of water to the boil in a pan and heat to 121 °C. Check the exact temperature with a thermometer
While the sugar syrup is boiling, whisk the egg yolks in a food processor until they have doubled in volume. Add the hot sugar syrup to the egg foam and continue beating for 10-20 seconds. The egg yolks are now pasteurized.
Pour the egg yolk mixture into a bowl, stir in the vanilla, Marsala and, in small portions, the mascarpone.
For the egg whites, also boil 60 g each of sugar and water to 121 °C.
In a clean bowl, beat the egg whites with a whisk until stiff and pour the hot syrup into the mixer with the beaten egg whites. This also pasteurizes the egg whites and makes them safe to eat.
Now pour the coffee into a bowl or shallow baking dish. Dip each sponge biscuit individually into the liquid. Only dip the cookies very briefly so that they do not become soft and fragile and line the bottom of a baking dish with them.
Cover the layer of soaked Savoiardi with crème and smooth with the help of a palette knife.
Spread another layer of soaked sponge fingers over the crème and cover with a final layer of crème.
Dust with cocoa powder to decorate and leave to stand in the fridge for at least 4 hours.