For convenience, you could buy the sponge fingers and the custard ready-made, in the same quantities as above, instead of making your own.
To make the sponge fingers (makes 16)
Pre-heat the oven to 200°C. Line a baking sheet with baking parchment.
Whisk the egg and sugar in a big bowl until light and quite stiff. Sift half the flour over the mixture and fold in lightly. Add the remaining flour. Spoon the mixture into a piping bag with a 1cm nozzle.
Pipe the mixture onto the baking sheet in 5 cm lengths, set apart because they expand while in the oven.
Bake in the prepared oven for 10 minutes, till golden. Leave to cool on a wire rack.
To make the custard (makes 300ml)
In a bowl beat the eggs, sugar and 50 ml of milk.
Put the rest of the milk in a non-stick saucepan with the vanilla seeds or vanilla bean paste. Bring the milk to the boil.
Set the milk aside to cool for 10 minutes then pour onto the egg mixture.
Mix well then strain the custard mixture into a clean saucepan and place back onto medium heat.
Keep stirring while the custard cooks and take off the heat when it is thick enough to coat the back of a spoon. Set aside to cool.
To assemble the trifle
Slice the Sweet Eve strawberries into thin slices. Whisk the fresh cream with the caster sugar until it forms soft peaks.
Take a deep trifle bowl and assemble alternate layers of strawberry slices, sponge fingers, custard and whipped cream. You may wish to arrange the strawberry slices so that you can see them in a row through the glass.
Decorate the top of the trifle with more Sweet Eve strawberry slices.