How funny is it that I found this recipe for an all-American dessert on a British website?!?
MAKES 1 X 20cm-23CM (8IN-9IN) CAKE
4 medium egg yolks
100g (3½ oz) golden caster sugar
1 tsp vanilla extract
25g (1oz) cornflour
500ml (18fl oz) whole milk
150g (5oz) plain flour
1 tsp baking powder
150ml (5fl oz) whole milk
30g (1¼ oz) unsalted butter diced
2 medium eggs plus 2 egg yolks extra
200g (7oz) golden caster sugar
100g (3½ oz) dark chocolate about 70 per cent cocoa solids
100ml (3½ fl oz) double cream
KITCHEN KIT Select a loose-bottom cake tin 20cm (8in) across and about 7cm (2¾ in) deep; alternatively, use a 23cm (9in) tin for a shallower cake.
FILLING Whisk the egg yolks, sugar and vanilla in a large bowl, then whisk in the cornflour. In a medium pan, bring the milk to the boil, whisk it on to the egg mixture, then return this to the pan and cook over a medium heat, stirring constantly (use a mini sauce whisk if you wish), to give a thick, smooth custard. Pour through a sieve into a large bowl, cover with clingfilm and leave to cool.
SPONGE Preheat oven to 180C/160C fan/gas 4. Sift the flour and baking powder together. Place the milk and butter in a small pan and heat until the butter melts. Whisk the eggs, extra yolks and sugar in a large bowl for 5 minutes using an electric whisk until thick, moussey and almost white. Fold in the flour mixture in three goes, then gradually whisk in the buttery milk, again in three goes, to give a smooth batter. Pour into the cake tin. Bake until the surface is set and spongy, about 35-40 minutes for a 20cm (8in) cake, 25-30 minutes for a shallower one. Leave to cool in the tin, then run a knife around the collar and remove it.
GLAZE Break up the dark chocolate and place in a small bowl. Bring the cream to the boil in a small pan and pour over the chocolate. Leave for 2 minutes, stir, then leave and stir again until combined into a smooth glaze.
TO FINISH Split the sponge in half horizontally. Stir the custard, then spread it over the bottom half of the sponge to within 1cm (½ in) of the rim. Sit the remaining half on top. Using a palette knife, smooth the glaze over the top, letting it trickle down the sides. Set the cake to one side in a cool place for a couple of hours to set. It will keep well loosely covered in the fridge for a couple of days, in which case remove 30 minutes before eating.