In a medium-sized mixing bowl, combine the espresso, vanilla extract, and cocoa powder. Whisk them together until well blended and set aside. This mixture will provide the coffee flavor that’s essential in tiramisu.

Using a stand mixer or a hand mixer (whatever gets the job done!), beat together the cold egg yolks and white sugar. Whip them for about 5 minutes, or until the mixture becomes pale and thick. It should have a lovely creamy texture. This step incorporates air for a light, fluffy result.

Once your yolks and sugar are ready, it’s time to add the kosher salt and the chilled mascarpone cheese. Whip them together until the mixture is smooth and creamy. This rich filling is the heart of your tiramisu.

In a separate bowl, pour in your heavy cream. Beat it until soft peaks form. This step is crucial for achieving that light, airy texture. Gently fold the whipped cream into the mascarpone mixture, being careful not to knock out the air you just whipped in.

Now comes the fun part! Take each ladyfinger and dip it quickly into the coffee mixture, ensuring they absorb some liquid without becoming soggy. I usually just count to three in my head before pulling them out. Start lining a 7x11 baking dish with the dipped cookies, laying them in a single layer.

Once you've laid out your first layer of ladyfingers, use a spatula to spread half of the mascarpone cream mixture evenly over them. Dust the surface with cocoa powder for that classic chocolate finish. Now, repeat the process; add another layer of dipped ladyfingers followed by the remaining mascarpone mixture, and finish with more cocoa powder on top.

Cover the baking dish tightly with plastic wrap and let the tiramisu chill in the refrigerator for at least 2 hours, though overnight is even better. This resting period allows all the flavors to meld beautifully.