507711655-Opera-Patisserie-Cedric-Grolet-1

¼ cup (60 g) cocoa butter
7 tablespoons (100 g) unsalted butter
¼ cup (60 g) mascarpone cheese
For the seed mixture
¾ cup (120 g) flaxseeds
⅔ cup (90 g) sunflower seeds
½ cup (70 g) pine nuts
⅓ cup (55 g) black sesame seeds
⅓ cup (55 g) white sesame seeds
5 teaspoons (25 g) chia seeds
For the croissant dough
Make a croissant dough following the directions on this page, using 1
¾ cups (420 g) of water.
For the pastry cream
Soak the gelatin in cold water. In a saucepan, heat the milk with the
cream. Halve the vanilla beans lengthwise, scrape out the seeds,
and add the seeds and pods to the saucepan to infuse for 20
minutes. In a bowl, whisk the superfine sugar, custard powder, flour,
and egg yolks until pale. Pass the hot milk-cream-vanilla mixture
through a conical sieve, then pour it over the egg yolk mixture.
Return to a clean saucepan and cook over medium heat, whisking
constantly, for 2 minutes, until thick. Remove from the heat and add
the cocoa butter, then the drained gelatin, butter, and finally the
mascarpone. Use an immersion blender to mix, then cool rapidly in
the refrigerator for about 30 minutes.
For assembly and finishing
Roll out the dough to a thickness of ⅛ inch (3.5 mm) and into a
rectangle, then use an offset spatula to spread the pastry cream over
the top. Mix all the seeds together. Sprinkle the seed mixture over
the dough, then roll tightly into a cylinder. Freeze for 20 minutes.
Cut the semifrozen cylinder into 1½-inch (4-cm) slices, place them in
greased cake rings, cover with a cloth, and let rise for 2 hours at