You will also need a 3-pint (1.75-litre) glass serving bowl .
First of all, split the trifle sponges in half length ways, turning them on their sides and cutting through, then spread each half with raspberry conserve, sandwich them together again and cut each one into three.
Next, arrange the pieces in the base of the bowl, make a few stabs in the sponges with a sharp knife and sprinkle the Madeira all over them as evenly as possible. Leave it now for about 30 minutes so the sponges can absorb the Madeira, tipping the bowl from side to side occasionally to distribute the liquid.
Make the custard.
Split the vanilla pod lengthways and, using the end of a teaspoon, scoop out the seeds.
Then place the pod and the seeds in a small saucepan, along with the cream.
Now place the pan over a gentle heat and heat it to just below simmering point. While the cream is heating, whisk the egg yolks, cornflour and sugar together in a medium bowl using a balloon whisk.
Next, remove the vanilla pod from the hot cream.
Then, whisking the egg mixture all the time with one hand, gradually pour the hot cream into the bowl.
When it’s all in, immediately return the whole lot back to the saucepan using a rubber spatula.
Now back it goes on to the same gentle heat as you continue whisking until the custard is thick and smooth, which will happen as soon as it reaches simmering point.
If you do overheat it and it looks grainy, don’t worry, just transfer it to a jug or bowl and continue to whisk until it becomes smooth again.
Toast the almonds under the grill, watching them like a hawk – they need to be golden brown, not black! Now, slice the bananas quite thinly and scatter them, along with the raspberries, in amongst the sponges.
Then whip the double cream with an electric hand whisk until it is firm but still floppy.
Pour the custard over, then spread the cream over the top and scatter with the cooled nuts.
Cover with clingfilm and store in the fridge till needed.