Devil’s Food Cake with Crunchy Hazelnut Filling

The star of this cake is the crunchy, nutty filling – reminiscent of crushed Ferrero Rochers sandwiched between dark cake layers that aren’t too sweet.

The whole thing is then covered with a luscious water ganache that’s intensely chocolatey. This ganache is made using water instead of cream, and nooo your ganache will not seize up. Instead you’ll get a frosting that isn’t too rich, where the chocolate takes center stage (so get a good chocolate).

Had to give myself a little pat on the shoulder for thinking of sugar cones as a stand-in for feuilletine. Feuilletine is often used in cakes to add some crunch…and basically tastes exactly like sugar cones. Yeah it wasn’t that much of an innovation thinking of a substitute.

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I went a little bit too enthusiastic with the decoration, dashing my lofty plans of an elegant cake and instead getting this wild creation.

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I got this recipe from David Lebovitz (he of all things chocolate) and just added the hazelnut crunch in the middle.

Ingredients (makes a 2-layered 8″ cake)


  • 9 tbsp unsweetened cocoa powder (66g)
  • 1 1/2 cups cake flour (188g)
  • 1/2 tsp salt
  • 1 tsp baking soda
  • 1/4 tsp baking powder
  • 4 oz unsalted butter, room temperature (113g)
  • 1 1/2 cups granulated sugar (300g)
  • 2 large eggs, room temperature
  • 1/2 cup strong coffee
  • 1/2 cup milk

Ganache frosting

  • 10 oz bittersweet chocolate, I used 70% (283g)
  • 1/2 cup water
  • 3/4 unsalted butter (170g)

Hazelnut crunch layer

  • 175g hazelnut paste/butter
  • 175g feuilletine (I used some crushed sugar cones as a substitute, see notes)
  • 75g white chocolate
  • Pinch of salt



  1. Sift the cocoa powder, cake flour, salt, baking soda, and baking powder together.
  2. Beat the butter and sugar until fluffy. Add the eggs one at a time until incorporated.
  3. Stir the coffee and milk together. Stir half of the dry ingredients into the butter mixture. Mix the milky coffee in. Then stir in the remaining dry ingredients.
  4. Bake at 180°C for 25 mins (see notes).

Ganache frosting

  1. Melt the chocolate with the water over a double boiler. Cut the butter into small pieces and whisk into the chocolate until smooth.
  2. Cool for 1h at room temperature until spreadable.

Hazelnut crunch layer

  1. Melt the white chocolate either over a double boiler or very carefully in the microwave on the lowest setting.
  2. Mix in the hazelnut butter and salt.
  3. Stir in the feuilletine.


  1. Put a little bit of frosting on your plate so your cake is secured to the plate.
  2. Spread a layer of frosting onto your first layer of cake. Spread a layer of the hazelnut crunch layer on top. Then place your second layer on top of that.
  3. Cover the whole thing in frosting and decorate. I used cocoa nibs, toasted hazelnuts, Maldon salt, and some leftover feuilletine.


  • If you don’t have feuilletine, you can substitute with some ice cream sugar cones like I did, or with crispy rolled crepes (the biscuits that kind of look like this or this).
  • The hazelnut butter I used was the one from whole foods, where it’s made from pure ground nuts.
  • My cake took closer to 35 mins to bake, though that might be my oven’s problem.
  • My ganache did not set at room temperature and I had to refrigerate it to get it to the right consistency. Since I refrigerated it the ganache was no longer shiny and pretty D: Some other people seems to have the problem as well, although many do not have this issue. For me I think it’s because my kitchen’s pretty warm right now. To solve this issue you can either refrigerate it like I did or add icing sugar to desired stiffness.
  • This cake tastes best at room temperature, eaten on the day it was made.

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