507711655-Opera-Patisserie-Cedric-Grolet-1

For assembly
Fresh blueberries
1 egg yolk
For the Basque shortbread pastry dough
In a bowl, mix the butter and brown sugar. Add the eggs, then the
flour, ground almonds, yeast, and salt. Using a rolling pin, roll out the
dough to a thickness of ⅛ inch (3 mm), then freeze for 40 minutes.
For the almond cream
In an electric stand mixer fitted with a flat beater attachment, beat
the butter with the piloncillo sugar and ground almonds for 10
minutes. Gradually add the eggs and whip for 2 to 3 minutes.
For the blueberry preserves
Set aside a few fresh blueberries for the garnish. Put the blueberries
with ¼ cup (50 g) superfine sugar in a vacuum-sealed bag. Steam at
210°F (100°C) for 20 minutes. Pour into a saucepan, then whisk in
the mixture of the ¼ cup (50 g) remaining sugar and pectin. Boil for 3
minutes, cool quickly, then transfer to a pastry bag.
For assembly and finishing
Preheat the oven to 350°F (175°C). Line the bottom and edges of a
rectangular pan with the dough. Fill with almond cream. Pour the
blueberry preserves over it, then add a few fresh blueberries on top.
Place a rectangle of Basque shortbread pastry on top.
Using a brush, glaze the dough with egg yolk. Then, using a fork,
score stripes. Bake in the oven for 30 minutes.