How to make
Start off with the cake layers by beating the eggs, vanilla sugar, a pinch of salt and the sugar into an ethereal fluffy cream. I recommend beating it in a water bath at 100°F (40°C) for 6 minutes and then the same amount outside the water bath.
Add the flour and starch in portions and mix with smooth movements with a spatula, so that the volume does not decrease.
Pour it into a greased and floured cake tin with a detachable bottom - 8.7″ (22 cm) in diameter and bake it at 320°F (160°C) for about 17 minutes or until it is fully baked. Leave the baked cake layer to cool on a wire rack.
Prepare the cream by heating the milk and cream. Add the sugar and vanilla sugar and stir, until they melt.
Hydrate the gelatin in cold water for 2-3 minutes or according to the manufacturer's instructions.
Beat the yolks with the starch and pour them over the milk. Crush the chocolate inside along with the butter. Boil the cream on low heat, while stirring constantly, for 8-10 minutes.
Remove it from the heat when it's ready and do not stop stirring - so not only will it not aquire a crust, but the temperature will drop slightly.
Add the hydrated and strained gelatin and mix everything well again.
Immediately place a layer of cling film on the cream, wait for it to cool and put it in the fridge.
It's time for the eclairs. For them, melt the butter in water over medium heat. Add a pinch of salt, sugar and flour. Stir, until a steamed dough is obtained, which separates from the walls of the cookware. Remove it from the heat and wait 10-15 minutes, then beat the eggs one by one and beat with a mixer, until a perfectly smooth mixture is obtained.
Fill the mixture into a piping bag and form the eclairs in a tray onto baking paper. Leave space between them, because they will rise when baking.
Bake them at 390°F (200°C) in a preheated oven for 20-25 minutes.
When they are ready, do not take them out immediately, just open the oven door and leave them inside for 15 minutes, then cool them completely.
Boil the syrup and leave it to cool. Beat the cream, which has been refrigerated for several hours, with a mixer. To 1/3 of it, add 1 cup (250 ml) of the whipped cream and beat well with a mixer.
Fill the eclairs with some of the eclair cream without the whipped cream (you may have some leftover).
Cut the cake layer longitudinally in the middle.
Start assembling it.
Place one half of the cake layer in a cake tin or on a tray with a fixed base. Syrup it and pour two fingers of cream without the whipped cream. Arrange the eclairs tightly next to each other, sprinkle with fresh blueberries and 2-3 tablespoons of jam and pour the remaining cream plus the other one, if you do not have enough. Put the second cake layer and syrup it as well. Set aside some of the cream with the whipped cream to spread on top or add all of it to cover the eclairs before adding the second layer - whatever you like.
If you have chosen the second option, the remaining 4/5 cup (200 ml) of cream will be used to spread on the last layer, mixed with a spoonful or two of blueberry jam. Otherwise, these components are excluded and the eclair cake remains completely white - you choose how to do it.
Decorate the blueberry eclair cake with the rest of your eclairs, optionally dipped in melted white chocolate and add more fresh blueberries.
Enjoy!
