1. Prepare a 17 X 24 cm tray that has a high edge. First prepare the lower sponge finger layer. Pour espresso coffee in a bowl and add rum and some castor sugar according to taste (it should have a slightly sweet and slightly rum taste), then stir until well combined.
2. Now one by one dip one half of the sponge fingers - only for 2-3 seconds - in the coffee liquid, and place tightly on the bottom of the tray. When ready, put the rest of the coffee liquid and the sponge fingers aside, you will need them later.
3. Now at medium heat bring a pot of water to a boil. In a bowl mix the whole eggs with the sugar, and when the water is boiling, put the mixture over the steam. Stirring regularly, heat the egg-sugar mixture until quite hot.
4. While the egg is being heated over steam, whip the refrigerated cream until very stiff, then put back in the fridge. Soak the gelatine sheets in some lukewarm water. Put the mascarpone in a small bowl, stir until smooth, then put aside.
5. In the meantime the eggs has reached the desired temperature. Take off the steam, and beat at maximum speed until cooled down.
ATTENTION! Don't be impatient, whip really until cooled down, otherwise our cream will be watery!
6. When the egg mixture cooled down, start to prepare the cream. Take out the whipped cream from the fridge and cautiously add the mascarpone. Finally add the whipped egg and combine with the whipped cream, stirring slowly.
7. Previously you needed to pour water on the gelatine sheets, now pour the water off, put in a bowl, and melt it at the minimum possile heat, stirring constantly - this would take about 10-20 seconds.
ATTENTION! Do not boil the gelateine, nor heat it until hot. As soon as it dissolves, it's ready!
8. Now in a thin stream, by constant stirring, add the gelatine to the cream. Take care to dissolve it well! The filling is thus ready.
9. Spoon the half of the filling on the soaked sponge fingers, spread evenly, than place the rest of the well soaked sponge fingers on top.
10. When ready, cover the seconmd layer of sponge fingers with the remaining cream, level it, then put the tiramisu in the freezer.
11. After freezing cut the tiramisu around with a knife previously dipped into hot water, slice, decorate with cocoa powder. Can be served melted up or scooped like ice-cream.
ATTENTION! Freezing is the fastest way to make your tiramisu ready. However, regarding taste, the best is to keep your tiramisu in the simple fridge for 6-8 hours to mature.