Separate the eggs, and place the whites in a big bowl, that has to be dry and clean; and the yolks in another bowl which then you´ll cover with plastic wrap so that it doesn´t curd. Set aside until needed.
Using a mixer, beat the egg whites with half of the sugar for 4 minutes until peaks form.
In a different bowl, beat the egg yolks with the rest of the sugar and vanilla until the mixture turns fluffy, lighter in color and a number eight can be formed with the string of batter without breaking.
Incorporate the egg whites to the beaten egg yolks using a rubber spatula, doing a circular motion, from the outside in until everything is well combined.
Carefully incorporate the sifted flour and salt in three different additions and mix.
Pour the mixture into two separte rectangular or square molds lined with parchment paper and spread using a spatula.
Bake at 350°F (180°C) for 15 minutes or until the cake starts turning golden brown on the sides.
Let it cool down completely before using.
For the coffee syrup:
In a small pot, boil toguether water and sugar for about 5 minutes.
While it´s still hot, pour in the instant coffe.
Once is room temperature, add the rum and set aside.
For the cheese filling:
Beat egg yolks and granulated sugar in a metal bowl over a pot of barely simmering water until the mixture is pale yellow and almost tripled in volume. Remove from heat and allow to cool for a couple of minutes.
In a separate chilled bowl, whip the heavy cream using a hand mixer until soft peaks form.
In another bowl, cream toguether the cream cheese, sour cream, powdered sugar, vanilla extract and salt. Add the yolks mixture and beat until fluffy.
Then, carefully incorporate the whipped cream to the cream cheese mixture and mix.
Put in the fridge until needed.
To assemble:
Place one of the cakes on the bottom of the mold you will be using to present the tiramisu in and brush it with half of the coffee syrup. Then spread half of the cream cheese filling.
Repeat the pervious step to finish it all off with a cream cheese mixture layer.
Decorate the tiramisu topping it with cocoa powder and or shaved chocolate.
Refrigerate for at least 2 hours prior to serving.