In a small saucepan
over medium heat, combine the sugar with the lemon juice
. Cook until the sugar
has dissolved, about 5 minutes. Let cool.
In a medium bowl, combine the cooled sugar mixture with the mascarpone cheese
and the lemon zest
. Using an electric mixer
on medium speed until the mixture is light and fluffy.
To build the trifle
, line the bottom of a trifle bowl with a layer pound cake. Brush the pound cake
with some creme de cassis liqueur
. Spoon a layer of the cheese mixture over the pound cake, and then a layer of berries. Repeat the layers until all the ingredients are used, finishing
with a top layer of berries. Chill in the refrigerator until ready to serve. Garnish with chopped mint