01 - In a medium mixing bowl, whisk cold milk and instant vanilla pudding mix together for 2 minutes. Allow the mixture to set for 5 minutes until thickened.
02 - In a chilled mixing bowl, combine heavy whipping cream, powdered sugar, and vanilla extract. Beat with an electric mixer or whisk until stiff peaks form. Set aside.
03 - Arrange half of the cake cubes evenly at the bottom of a large glass trifle bowl.
04 - Spoon one-third of the prepared pudding over the cake cubes. Smooth one-third of the whipped cream on top.
05 - Scatter half of the sliced strawberries and blueberries evenly over the cream layer.
06 - Repeat layering with the remaining cake cubes, another third of the pudding, another third of the cream, and the remaining raspberries, strawberries, and blueberries.
07 - Spread the final portion of pudding and whipped cream on top. Garnish with extra fresh berries and white chocolate shavings if using.
08 - Refrigerate the assembled dessert for at least 2 hours to allow the flavors to meld before serving.