Put the raisins in a saucepan and add 200ml Marsala. Bring to just under the boil, remove from the heat and leave the raisins to plump up.
For the custard, put the egg yolks, sugar and cornflour in a large bowl and mix well. Heat the milk, cream and vanilla in a large saucepan until just below boiling, then take off the heat and slowly pour them over the sugar and egg mixture, whisking continuously.
Clean the pan, put the egg and cream mixture into it and whisk over a medium-low heat for 2-3 minutes, stirring all the time, until thickened. If any lumps appear, whisk the mixture or beat hard with a wooden spoon until it’s smooth. Pour into a large bowl and cover with cling film. Leave to cool completely.
Put the wine, 200ml water, the sugar and the lemon rind into a saucepan and heat, stirring to help the sugar dissolve. Add the vanilla extract. Put the pears into the pan and poach gently until the flesh is just soft (how long this takes depends on how ripe the pears are).
Leave the pears in the liquid until they’re cool (they will develop a lovely flavour as they sit).
Put the hot coffee into a dish. Add the light-brown sugar and the rest of the Marsala. Dip the sponge fingers in the coffee mixture and lay them (two for every portion) in the bottom of eight glasses (each with a volume of about 250ml), breaking them up as necessary.
Spoon the raisins on top of the sponge. Scatter on the nuts and sift some of the cocoa powder over the top. Slice the pears thickly and divide them between the glasses, then add custard.
Put the glasses into a roasting tin – or something similar – put cling film over the top, then put them into the fridge for 2 hours.
Before you want to serve the trifles, sift some cocoa on top of the custard. Whip the cream and add the caster sugar. Spoon this on top of each trifle. Sprinkle the rest of the cocoa powder on top and serve.