- Whip the yolks with buttermilk cocoa, flour, baking soda, and the sweetener. Whisk the whites with a pinch of salt until stiff. Carefully combine both masses.
- Bake the cake at 392°F (200°C) for 35-50 minutes.
- Check the readiness with a match (it must be dry). Wrap the cooled biscuit in a cling film and leave it in the fridge overnight.
Defrost and chop the frozen berries, put them in a saucepan with other ingredients, and cook until thickened.
Soak hazelnuts in water for 4-5 hours, then peel and roast them in a dry pan until golden.
Mix all the ingredients until smooth.
- Cut the cooled sponge biscuit into 4 layers
- Spread the frosting over the first layer, forming the borders, and put the jam in the center.
- Spread the frosting over the second layer.
- With the third one, do the same as with the first layer.
- Decorate the cake with nuts, and place it in the fridge overnight.