01 - In a medium bowl, combine strawberries, blueberries, raspberries, and optional sugar. Gently toss and let stand for 10 minutes to allow berries to release their juices.
02 - In a large mixing bowl, whip heavy cream to soft peaks. Add mascarpone or cream cheese, granulated sugar, and vanilla extract. Continue whipping until the cream is thick, smooth, and fully combined.
03 - If making homemade custard, prepare according to your preferred recipe and cool completely before proceeding.
04 - Arrange half of the cake cubes in the bottom of a trifle bowl or individual serving glasses, creating an even layer.
05 - Spoon half of the macerated berries with their juices evenly over the cake cubes.
06 - Spread half of the vanilla custard over the berries, ensuring even coverage.
07 - Spread half of the vanilla cream mixture evenly over the custard.
08 - Repeat the layering order with remaining cake cubes, berries and juices, custard, and vanilla cream.
09 - Decorate the surface with extra berries and fresh mint leaves if desired. Cover and refrigerate for at least 1 hour before serving to allow flavors to develop.