Sliced limoncello and berry trifle cake

Method

1. To prepare the tin, line the sides with lengths of strong foil folded in half to give extra rigidity. Start with the longer sides of the tin, ensuring the foil comes about 6cm above the height of the tin, then repeat with the remaining sides. (The mixture is slightly larger than the tin but it’s not very weighty, so you just need the foil to extend the tin a bit.)
2. Put 400g of the berries in a mixing bowl. Add the lemon juice, icing sugar and most of the limoncello, reserving 2 tbsp. Set aside to macerate for 1 hour.
3. Soak the gelatine leaves in a small bowl of cold water to soften for 5-8 minutes. In a bowl, whisk the egg yolks and caster sugar for 5 minutes until thick and pale. Using a wooden spoon, beat the mascarpone and lemon curd in a separate bowl to soften. Gradually add the mascarpone mixture to the egg yolk mixture, stirring after each addition, until incorporated.
4. In a small pan, heat the cream until steaming (don’t boil), then turn off the heat. Squeeze the gelatine to remove any excess water, then stir it into the hot cream until fully melted. Add a spoonful of the egg/mascarpone mixture to the gelatine cream, mixing well. Stir this gelatine mixture back into the egg/ mascarpone mixture, then gently mix to combine.
5. Whisk the egg whites in a large clean bowl to stiff peaks (that won’t flop over when you lift the beaters out). Stir 1 large scoop of the egg whites into the mascarpone cream, then gently stir/fold in all the remaining egg whites to give a thick, light, mousse-like mixture.
6. Lay one third of the sponge fingers evenly over the base of the prepared tin. Add half the macerated berry mixture with half their juice. Top with half the mascarpone cream, then smooth into an even layer. Repeat the layers, then finish with a final layer of sponge fingers. Drizzle the reserved 2 tbsp limoncello over the sponges, then cover with cling film. Chill for at least 4 hours or overnight.
7. When ready to serve, remove the cling film from the tiramisu, then carefully invert the tin onto a serving plate or board. Peel off the foil, then top with the remaining berries and pistachios. Cut into generous slices to serve.