Separate egg yolks and egg whites in to two separate bowls. Add sugar to egg yolks. Mix with a hand or stand mixer until yolks and sugar have completely combined.

Once combined, add mascarpone cheese. Mix until combined well.

Put heavy cream under mixer and mix until it has become fluffy and whipped. Combine egg/mascarpone mixture with newly whipped heavy cream in larger bowl. Chill in fridge while making the limoncello mixture.

Put limoncello on stove and boil with water and sugar. Add water and sugar. You want to add half the amount of water and a quarter amount of sugar for as much limoncello as you have put on the stove.

When limoncello begins to boil, add half a lemon's worth of lemon juice. You only need to boil the combination for about a minute to burn off the alcohol. Chill for 30 minutes minimum.

Begin building your tiramisu. Add a layer of mascarpone/cream to the bottom of your dish. Then, add a layer of limoncello soaked ladyfingers. Depending on preference, you can soak the ladyfingers anywhere from 10 seconds to a few minutes but don't soak them too long or they will get too soggy to use. Repeat steps until all ingredients are used up or dish is filled. Top layer should be a layer of the mascarpone/cream mixture.

Finally, top with lemon zest and cocoa powder. Chill for 30 minutes minimum or until ready to serve.