Mix instant coffee into the sponge finger batter. Form the fingers shorter than usual and also baking them a bit shorter than usual.

Soak the gelatine in cold water. Combine the mascarpone, egg yolks, and sugar, blending them until smooth. Beat the egg whites and sugar until creamy. Dissolve the gelatine over a warm bain-marie, adding a bit of the mascarpone cream. Fold the dissolved gelatine into the mascarpone cream and then gradually fold in the egg whites in three steps.

Line cake rings 8 cm in diameter with foil. Soak a few sponge fingers in the simple syrup-and-rum mixture and distribute them within the rings. Pipe some cream into the cake rings and place a further layer of soaked sponge fingers on top. Finish by piping on the rest of the cream. Now firm up the tiramisu by chilling it in the refrige­rator for 60 minutes.

Finish by drizzling on a bit of chocolate rum sauce or sprinkling with cocoa powder.