Preheat oven to 175°C/155°C fan/gas 3.5. Mix the custard powder, 40g sugar and 5 tblsp milk until smooth. Boil 375ml milk and stir in the pudding mix. Simmer for 1 minute then remove, cover and allow to cool.
In a bowl, mix 75g caster sugar and custard powder with 100ml milk and stir until smooth. in a pan, heat 350ml milk then add the custard powder mixture, bring to the boil then simmer for 1 minute. Remove from the hob and transfer to a bowl, cover with foil and allow to cool.
In a bowl, mix the flour, cocoa, icing sugar and a pinch of salt. Add the butter, 1 egg and 1 tbsp cold water. Knead with the dough hook of a mixer, then with your hands to a smooth dough. Wrap in cling film and chill fo...
Cook the blueberries with 75g of the sugar. Cool and refrigerate. Split the vanilla pods and scrape out the seeds. Mix the seeds with the eggs, a pinch of salt and the remaining sugar in a bowl. Set this over a pan of simmering water and whisk until the sugar has dissolved. Remove from the water bath and whisk until frothy. Whisk the cream until stiff and fold into the egg mixture.
For the ganache: briefly bring the cream to the boil, remove from the heat and stir in 200g of the chocolate until it melts. Pour into a large mixing bowl, cover surface directly with foil and refrigerate for several hours, preferably overnight.
Preheat oven to 175°C/155°C fan/gas 3.5. In a bowl, mix together the flour, baking powder and sugar. In a separate bowl, whisk together the egg, milk and oil. Add the flour mixture then stir in the cherries and chocolate. Divide mixture between 6 small, greased, oven-proof glasses with airtight seal-able lids, about 290ml capacity. bake in the centre of the oven for about 35 minutes, until a knife inserted comes out clean.