01 - Combine strawberries, blueberries, raspberries, and optional sugar in a medium mixing bowl. Gently toss and set aside for 10 minutes to release juices.
02 - In a large bowl, whip heavy cream to soft peaks using an electric mixer or whisk. Add mascarpone or cream cheese, granulated sugar, and vanilla extract. Continue whipping until smooth and thick.
03 - If using homemade custard, cook according to your preferred method, allow to cool completely. Use prepared pudding as an alternative.
04 - Place half of the cake cubes in the bottom of a trifle bowl or serving glasses.
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, then dollop and spread half of the vanilla cream mixture on top.
07 - Repeat the layers with the remaining cake, berries, custard, and vanilla cream.
08 - Top with extra berries and garnish with fresh mint leaves, if desired. Cover and chill for at least 1 hour before serving.