Blueberry gâteau basque (cake) (Cédric Grolet)

A new gâteau basque here, in a fruity and seasonal version this time! I found this recipe in Cédric Grolet's book Opéra, and here it is, with a few modifications due to too many quantities or mistakes. It's a rather easy cake to make, but you have to respect the cooling and resting times for the dough (it's a very buttery dough so it's much easier to work with when it's cold).
 
 

 
 Prep time : 1 hour + 30 minutes cooking
 For 10 servings | a 30x11cm cake :

 

The dough :

 250g butter
 220g cassonade sugar
 90g egg
 310g T55 flour
 155g almond powder
 4g baking powder (instead of 160g indicated in the book ^^)
 3g of salt
 
 Given the leftover dough I had, I think you can decrease the proportions by using one egg (50-60g) instead of 90g.

 Mix the butter with the brown sugar.
 
 

 
 Add the egg, then the flour, almond powder, baking powder and salt.
 
 

 

 
 When the dough is homogeneous, divide it into two parts, then roll out each part to a thickness of 3mm between two sheets of baking paper.
 
 

 
 Put them in the freezer for 40 minutes (I put them in the fridge for 1 hour instead).
 
 

Almond cream :

 15g butter
 30g sugar
 100g almond powder (30g in the original recipe, but the cream obtained was too liquid for me)
 125g eggs
 
 Mix the butter with the sugar and almond powder in a food processor for about 10 minutes.
 
 

 
 Then add the eggs, continuing to mix for 2 to 3 minutes. Keep the almond cream in the refrigerator until ready to assemble.
 
 

Blueberry compote : 

 500g blueberries
 50g sugar
 5g NH pectin
 
 In the book the quantities were twice as important (1kg of blueberries for 100g of sugar and 10g of NH pectin), I reduced everything by 2 and it was enough.

 Reserve a few fresh blueberries for the assembly.
 Original recipe: put the blueberries with half the sugar in a vacuum bag and cook for 20 minutes at 100°C. Pour into a saucepan and add in the other half of the sugar previously mixed with the pectin. Let boil for 3 minutes, then cool.
 My version, without vacuum cooking: put the blueberries in a saucepan and cook them over low heat, stirring regularly, until you get a compote.
 
 

 
 Whisk in the sugar and pectin and cook for 3 minutes after boiling. Allow to cool.
 
 

 
 

Assembly and cooking :

 1 egg for egg wash
 
 Fill your frame or mold with the first dough.
 
 

 
 Garnish with the almond cream, then the blueberry compote and finally the fresh blueberries.
 
 

 

 

 
 Cover with second dough, then place in refrigerator for 15 minutes. Put some egg wash on it, then chill for 15 minutes. Do it again and then mark the dough with a knife blade.
 
 

 
 Prick the cake in a few places so that it doesn't explode during baking.
 Bake in the preheated oven at 175°C for 30 minutes. Let cool, then enjoy!