Prepare vanilla pudding mix with cornstarch as directed on package, ensuring it thickens.

Beat heavy whipped cream with castor sugar until thick and spreadable.

Cut jelly roll into slices.

Line the bottom and sides of a large crystal bowl with the jelly roll slices.

Prepare jello mix as directed and spoon some of the cooled jello over the jelly roll to moisten.

Set aside the remaining jello to slightly thicken.

Spoon fresh strawberries or raspberries on top of the jello-soaked cake.

Cover the berries with the remaining slightly thickened jello.

Let the jello and berry layer chill in the refrigerator until firm.

Pour the prepared vanilla pudding over the jello/fruit layer.

Place the trifle in the refrigerator to chill thoroughly.

Just before serving, cover the trifle with whipped cream.

Decorate the trifle as desired.

Keep the trifle refrigerated until serving time.

Serve the trifle into individual glass bowls.