17-Layer Chocolate Cake with Chocolate Cremeux

Ingredients

• Egg yolks (For the cremeux)
• Sugar (For the cremeux)
• Heavy cream (For the cremeux)
• Whole milk (For the cremeux)
• Dark chocolate (Chopped; for the cremeux)
• Flaky sea salt (A good pinch)
• Egg yolks (For the sponge)
• Sugar (Divided; for the sponge yolks and meringue)
• Egg whites (For the French meringue)
• Plain flour (Sifted)
• Cocoa powder (Sifted)
• Whole milk (For the sponge batter)
• Vegetable oil (For sponge flexibility)
• Chocolate mirror glaze (Optional finish)

Steps

1. 1

   In a saucepan, combine egg yolks, sugar, cream, and milk for the cremeux.

2. 2

   Whisk the mixture constantly over medium-low heat until it reaches 83°C (181°F) on a digital thermometer.

3. 3

   Immediately pour the hot custard through a sieve over your chopped chocolate. Let it sit for a few minutes to melt.

4. 4

   Use an immersion blender to blend the chocolate mixture until perfectly smooth.

5. 5

   Whisk in a good pinch of flaky sea salt. Cover the surface directly with plastic wrap (cling film) to prevent a skin from forming and chill in the fridge for 3 to 4 hours.

6. 6

   To make the sponge, whisk egg yolks and sugar together until the mixture is thick, pale, and leaves a trail. Set aside.

7. 7

   In a separate clean bowl, whisk egg whites on low speed until frothy. Gradually add sugar one tablespoon at a time, whisking until you have a thick, stiff French meringue.

8. 8

   Gently whisk one-third of the meringue into the egg yolk mixture to lighten it, then fold in the remaining meringue in two batches.

9. 9

   Sift plain flour and cocoa powder over the egg mixture and gently fold them through until no dry streaks remain.

10. 10

    Tip in the milk and vegetable oil, folding gently until you have a smooth, flexible batter.

11. 11

    Pour the batter into a silicon sponge roll mat or a baking tray lined with parchment paper. Spread it evenly to the edges.

12. 12

    Bake the sponge (typically at 180°C/350°F for 10-12 minutes, though not specified). Repeat the process to bake a second sponge.

13. 13

    Once the sponges are cooled and the cremeux has chilled to a soft, spreadable texture, spread the cremeux evenly over the sponges using a palette knife or a leveling tool.

14. 14

    Cut the coated sponges into 8 equal pieces each. Stack the pieces on top of each other to create the 17 layers (8 layers of sponge + 8 layers of cremeux + top glaze).

15. 15

    Chill the stacked cake in the freezer until firm and the cremeux is no longer wet to the touch.

16. 16

    Pour the chocolate mirror glaze over the chilled cake. Let the glaze set for a few minutes.

17. 17

    Using a very sharp knife, trim the rough edges to reveal the clean layers and cut into four equal rectangles.

Notes

The oil in the sponge is critical for flexibility, preventing it from cracking during assembly. The cremeux must reach exactly 83°C to ensure the eggs are cooked into a proper custard without curdling. Trimming the edges while the cake is semi-frozen ensures the cleanest presentation of the 17 layers.

Nutrition per serving

• dessert
• chocolate cake
• baking
• cremeux
• mirror glaze
• French pastry
• layered cake