Limoncello tiramisu

Bring the water to a boil over high heat and dissolve the 300 g sugar in it.

Zest the lemons and reserve the zest for the layers. Squeeze the juice of three lemons into the water.

Before it boils, add strips of lemon skin taken with a potato peeler, avoiding the white pith. Boil about 5 minutes.

Switch off the heat and add about 100 ml limoncello, so not all the alcohol is cooked off.

Transfer the syrup to a bowl and let it cool to room temperature, about an hour, or speed it up in the fridge. It must not be used warm.

Separate the eggs.

Beat the yolks with a hand mixer, starting on medium speed; add 3 tablespoons of sugar one at a time, then beat on maximum speed until creamy.

Combine the yolks with the mascarpone, add the juice of one lemon and mix.

Beat the whites, starting slow and speeding up, adding 3 tablespoons of sugar one at a time, until creamy.

Gently fold the whites into the yolk and mascarpone cream.

Add a generous amount of limoncello and mix.

Optionally cover and rest the cream in the fridge 20 to 30 minutes or more.

Dip each Savoyardi, sugar side down, in the syrup for three seconds, remove the excess and lay in the Pyrex; break pieces to close any gaps.

Spread a thick layer of cream, then a generous layer of white chocolate and the lemon zest.

Repeat a second layer of dipped biscuits, cream, white chocolate and lemon zest.

Cover with cling film and refrigerate at least 4 hours, best overnight; keeps up to about four days.

Cut into slices and serve.