Delight friends and family with this zesty, zingy trifle desert, combining fresh cream with intensely lemony Italian liqueur for a pudding with pizzazz. In a small pan, heat the sugar with 90ml (3fl oz) water over a low heat. Add the lemon zest strips and continue cooking for 10 minutes, or until syrupy. Use a strainer to remove the zest from the syrup and transfer to a cooling rack. Pour the syrup into a bowl and add the lemon juice and limoncello. Gently stir to combine, then set aside. In a separate bowl, gently whip the mascarpone, double cream and 2 tbsp of the lemon syrup with an electric whisk, to loose, soft peaks. One at a time, dip half the sponge fingers in the lemon syrup and arrange in the base of a trifle bowl. Top with half of the lemon curd, followed by half of the mascarpone mixture. Repeat with the remaining sponge fingers, and then top with the remaining lemon curd and mascarpone mixture. Scatter over the lemon zest strips. Transfer to the fridge, until ready to serve.