01 - In a medium mixing bowl, whisk together cold milk and the instant vanilla pudding mix for 2 minutes, then set aside for 5 minutes until thickened.
02 - In a chilled bowl, beat the heavy whipping cream with powdered sugar and vanilla extract using an electric mixer or whisk until stiff peaks form; refrigerate until needed.
03 - Arrange half of the pound cake cubes at the base of a large clear trifle bowl or serving dish.
04 - Spoon one-third of the vanilla pudding over the cake layer, then spread one-third of the whipped cream over the pudding.
05 - Evenly scatter half of the strawberries and blueberries over the cream layer.
06 - Repeat layering with the remaining cake cubes, another third of pudding and cream, followed by the remaining berries and raspberries. Finish with the final layer of pudding, then top with the remaining whipped cream.
07 - Garnish the assembled dessert with extra fresh berries and optional white chocolate shavings. Refrigerate for at least 2 hours before serving to allow flavors to develop.