01 - In a medium mixing bowl, combine cold milk and vanilla pudding mix. Whisk briskly for 2 minutes, then let stand for 5 minutes until fully thickened.
02 - In a chilled mixing bowl, beat heavy cream, powdered sugar, and vanilla extract using an electric mixer or whisk until stiff peaks form. Set aside.
03 - Place half of the cake cubes in an even layer at the bottom of a large glass trifle bowl or clear serving dish.
04 - Spread one-third of the prepared vanilla pudding evenly over the cake layer. Follow with one-third of the whipped cream, smoothing it gently.
05 - Scatter half of the strawberries and half of the blueberries uniformly over the cream layer.
06 - Layer with remaining cake cubes, then add a second third of pudding and cream. Arrange the raspberries and remaining berries evenly over the cream.
07 - Spread the final third of pudding and whipped cream on top. Garnish with extra berries and optional white chocolate shavings.
08 - Cover and refrigerate trifle for at least 2 hours to allow flavors to meld before serving.