Zest the lemon and put aside for garnish later.

Separately squeeze all of the juice out and set aside (you'll need about 4 tablespoons lemon juice).

Use 2 large bowls and separate the egg whites from the egg yolks.

Whip the egg whites with an electric mixer on medium speed until stiff peaks form and set aside (don't overbeat!).

Add the powdered sugar to the egg yolks and whip using the electric mixer.

Then add the limoncello, lemon juice and mascarpone cheese. Whip again until you've reached a nice creamy mixture (don't overwhip!).

Pour the whipped egg whites into the cream bowl and using a rubber spatula gently fold the whites into the cream (do this slowly and fold through gently, don't overmix).

In a deep bowl, add the milk, limoncello and powdered sugar. Whisk until well combined.

Using a large pyrex dish (13 x 9 inches / 30 x 22 cm) in size, one at a time, dip a savoiardi biscuit into the soaking mixture until fully submerged for 2-3 seconds at maximum. Place it into the pyrex dish on the edge of one side.

Keep repeating the above step and place the soaked biscuits next to each other in single layer. The biscuits should be covering the whole bottom of the dish.

Pour in just under half of the cream mixture straight on top of the biscuits. Using a spatula or the back of a spoon, gently smooth it out to an even layer so that all the biscuits are covered with a layer of cream.

Dip the remaining biscuits one at a time into the soaking mixture. Layer them next to each other in a single layer on top of the cream.

Pour the remaining cream on top, and using a spatula/back of a spoon, gently smooth it out to an even layer so all biscuits are covered.

Garnish with grated white chocolate, grated lemon zest and cover with plastic wrap. Place in the fridge for at least 8 hours, or even better overnight.

When ready to serve, remove from the fridge and leave it out for 5 minutes. Slice into pieces and enjoy your delicious Limoncello Tiramisu!