Cut open this lemony pudding to reveal swirls of blackcurrant sauce. It’s served with creamy vanilla egg custard, too.
Place an upturned saucer on the base of a large pan and fill about ⅓ full with hot water. Cover and set over a medium heat. Fold the greased disc of baking paper, greased side down, so it has a 3cm crease in the centre. Turn by 90 degrees and fold again, to create a cross. Repeat with the 27cm foil disc.
Make the pudding. Put the lemon zest into a bowl, then sift in the flour and mix. Put the butter, sugar and vanilla into another bowl and beat until creamy and light. Add the eggs one at a time, beating after each addition. Add in the flour and lemon and fold to combine.
Spoon the batter into the basin and spread evenly. Cover the top with the baking paper (greased side down), then the foil, and secure with string around the rim. Tie a doubled length of string across the top as a handle.
Put the basin in the pan, on top of the saucer, and add more hot water, so that it reaches about one third up the sides of the basin. Cover, and simmer gently for 2 hours. Check regularly and top up with hot water, if necessary.
Now, make the sauce. Put 150g of the blackcurrants into a pan with 100ml of water, the sugar and the lemon zest and set over a low heat. Stir to dissolve the sugar, then simmer for 5–7 minutes, until the blackcurrant juices have released and thickened.
Remove from the heat and stir in the remaining blackcurrants and the crème de cassis. Leave until cold, then strain into a jug. Tip the blackcurrants back into the pan and set aside. Pour the juice into the cooking syringe.
When the pudding is almost ready, make the custard. Pour the milk, cream and vanilla into a heavy-based, medium pan and heat gently. Remove the pan from the heat just before it comes to a boil. Put the egg yolks and sugar into a heatproof bowl and whisk for 2–3 minutes, until pale and smooth. Slowly pour in the hot milk mixture, whisking continuously, then tip the mixture back into the pan. Stir continuously over a medium–low heat until the custard thickens to coat the back of the wooden spoon – don’t let it boil. Pour into a warmed jug.
Lift the pudding from the pan. Remove the cover, loosen the sponge with a palette knife, and leave for 5 minutes to firm up, then turn out onto a warm serving plate.
Insert the syringe into the middle of the pudding and inject sauce while at the same time retracting the needle (to create stripes of sauce). Repeat all over the pudding.
Pour any remaining juice back into the pan with the fruit, warm through, then spoon a little over the pudding and serve the remainder in a warm jug. Serve with custard, too, if you like.