Choose a few attractive strawberries, raspberries, and blueberries and set them aside for decorating the finished trifle.

Place the raspberry jam in a large microwave-safe bowl. Heat for about 1 minute, or just until warm and fluid enough to easily coat the fruit.

Add the sliced strawberries, raspberries, and blueberries to the warm jam. Gently toss until the berries are evenly coated.

Set the berry mixture aside while preparing the cream, stirring it occasionally so the fruit remains coated in the developing juices.

Pour the cold heavy whipping cream into a large mixing bowl. Whip until stiff peaks form, then set aside.

In a separate large bowl, beat the softened cream cheese and confectioners' sugar until completely smooth and creamy.

Beat in the vanilla until evenly incorporated.

Add approximately one-third of the whipped cream to the cream cheese mixture and beat gently until combined. This lightens the mixture.

Add the remaining whipped cream and use a large rubber spatula to gently fold it into the cream cheese mixture. Continue folding just until smooth and fluffy.

Arrange a single layer of ladyfingers across the bottom of a 9-inch (23cm), approximately 14-cup-capacity glass trifle dish. Break the biscuits into smaller pieces where necessary to cover the bottom.

Spoon one-third of the berry mixture, including some of its juices, evenly over the ladyfingers.

Spread one-third of the cream cheese mixture over the berries.

Repeat the layers of ladyfingers, berry mixture, and cream two more times.

For the final cream layer of the Summer Berry Trifle, leave approximately a 1-inch border around the edge so some of the colorful berries remain visible through the glass.

Decorate the top with the reserved fresh berries and a sprig of mint, if desired.

Cover and refrigerate for at least 8 hours, preferably overnight.

Keep chilled until ready to serve, then spoon generously into individual dessert dishes.