507711655-Opera-Patisserie-Cedric-Grolet-1

¾ cup plus 3 tablespoons (180 g) superfine sugar
3 tablespoons (50 g) custard powder
⅓ cup (50 g) all-purpose flour
2½ tablespoons (25 g) potato starch
¼ cup (60 g) cocoa butter
7 tablespoons (100 g) unsalted butter
¼ cup (60 g) mascarpone cheese
For the croissant dough
Make a croissant dough following the directions on this page using
1¾ cups (420 g) of water.
For the lemon cream
Soak the gelatin in cold water. In a saucepan, heat the lemon juice
and zest. Mix the egg yolks, superfine sugar, custard powder, flour,
and potato starch, and pour over the lemon juice. Boil for 2 minutes,
add the cocoa butter, and mix. Stir in the drained gelatin, then the
butter, and finally the mascarpone. Mix and cool rapidly. Pour the
lemon cream over parchment paper, roll up to form a ¾-inch (2-cm)-
diameter cylinder, hold it in place with adhesive tape, and freeze for
1 hour.
For assembly and finishing
Using a rolling pin, roll out the dough to a thickness of ⅛ inch (3.5
mm) and cut out 8 by 20-inch (20 by 5-cm) rectangles. Cut the
frozen lemon cream into 2-inch (5-cm)-long tubes. Place each tube
on a dough rectangle and roll up. Let rise for about 2 hours. Preheat
the oven to 350°F (175°C).
Place each roll in a 2½-inch (6-cm)-diameter greased-and-sugared
circle. Bake in the oven for 25 minutes. Remove the pastries from
the oven and roll in superfine sugar.