Prepare the pie shell by following the instructions on the package and allow it to cool.

Melt the white chocolate in a microwave-safe bowl, heating in 20-second intervals until smooth.

Whisk half and half with the instant vanilla pudding mix until thickened, about 2-3 minutes.

Whip cold heavy cream and vanilla extract until soft peaks form.

Gently fold the melted chocolate into the pudding mixture until combined.

Fold in the whipped cream in batches until no streaks remain.

Spoon the mousse into the cooled pie shell and smooth the top.

Refrigerate for at least 4 hours or overnight to set.

Garnish with fresh berries just before serving.