Make up both jellies according to the packet instructions but using about 30ml less cold water than instructed.
Pour half of the passionfruit jelly into the bottom of the trifle bowl and add 3-4 sliced strawberries to the jelly. Place in the fridge to set.
Place remaining passionfruit jelly into a small container that will allow you to cut the jelly into cubes once set. Place the raspberry jelly into a separate container and place both jellies in the fridge to set.
Make up the custard by combining the custard powder and sugar with a little of the milk to make a paste. Heat the remaining milk in a saucepan. Once steam starts to rise from the milk and small bubbles form on the surface, add the custard powder paste and whisk the mixture until it thickens. Set aside to cool.
Slice jam sponge roll into rounds that are about 1 1/2cm thick. Once the passionfruit jelly has set in the bottom of the trifle bowl, place rounds around the edge of the bowl so you can see the swirl pattern and then place remaining rounds in the centre to create an even sponge layer.
For the next layer, spoon over your cooled custard and sliced peaches (draining the juice from the peaches first).
Once the jelly is set, cut into cubes and place over custard and peaches to create the next layer of your trifle.
Beat thickened cream and icing sugar until stiff. Use a piping tube to decorate the trifle with cream stars and then add remaining strawberries, sliced or chopped, to the top of the trifle.