507711655-Opera-Patisserie-Cedric-Grolet-1

2 vanilla beans
1½ ounces (40 g) white chocolate
For the softened butter
1 tablespoon (15 g) unsalted butter
For the chocolate cake
First, in an electric stand mixer fitted with a flat beater attachment,
mix the eggs, trimoline, sugar, and ground almonds. Second, a
separate bowl, mix the flour, baking powder, and cocoa powder, and
add this mixture to the first one. Stir in the cream (at room
temperature) and mix again. Add the grapeseed oil. Finally, add the
Guanaja chocolate, previously melted in a bain-marie.
For the vanilla cake
To make the batter, follow the first step for the chocolate cake above.
Second, add the vanilla (split and scraped beans) and melted white
chocolate. Continue the recipe as described above.
For the marbling and baking
Spoon some of the chocolate cake batter into the bottom of a
greased cake pan, then the vanilla cake batter on top. Repeat this
process twice to make six layers. Use a knife to make zigzags
through the different layers to create a marbling effect. Soften the
butter, pour it into a pastry bag without a tip, make a hole at the end,
and pipe a line of butter along the middle of the cake.
Preheat the convection oven to 360°F (180°C). Bake the cake for 20
minutes. Reduce the temperature to 320°F (160°C) and finish baking
for about 25 minutes.
Tip
Butter and flour your cake pan to prevent the batter from
sticking.
Let stand for 15 minutes before eating.