Separate the egg whites from the egg yolks.
In a bowl, beat the egg whites until they have a white and firm texture and form picks. To beat the egg whites until stiff we can use a whisk or a food processor.
Use another bowl to mix the egg yolks and sugar until you have a creamy texture.
With the help of a fork, soften the mascarpone cheese and add it to the egg yolks with the sugar.
Mix all the ingredients until the egg yolks are integrated with the mascarpone cheese.
Add the pistachio paste and mix again.
Finally, with the help of a spatula, we incorporate the mascarpone and pistachio mixture to the egg whites with soft movements. Use a spatula to avoid losing the texture of stiff peaks when mixing.
Now we prepare a coffee and mix it with our favorite liqueur (optional, you may not add liqueur). I've used Baileys.
We bathe our savoiardi or sponge cakes in the coffee and begin to set up our pistachio tiramisu.
We place a layer of savoiardi soaked in coffee, a layer of mascarpone and pistachio cream, another layer of savoiardi, and finally a layer of mascarpone and pistachio cream.
Decorate with cocoa powder (optional) and chopped pistachios.
Let it cool in the refrigerator covered with plastic wrap for 4 to 12 hours and enjoy your authentic Italian Pistachio Tiramisu!