Grease a rectangular cake tin with butter and sprinkle with almonds. Preheat the oven to 170 ° C without convection.
In a bowl, stir the eggs with sugar and vanilla for about 2 minutes until frothy. Mix in hazelnuts, baking powder, lemon fiber and coconut flour well. Chop the chocolate and stir in with the liqueur.
Fill into the prepared form and place in the oven for approx. 50 minutes. Make a chopstick test.
After baking, let cool on a rack. Melt the chocolate icing and cover the cake with it.
If you want, you can decorate the cake with hazelnut brittle. I had made it myself beforehand. Melt some Xucker Bronze in a pan and fold in the chopped hazelnuts. Immediately place on baking paper, allow to cool and break into small pieces. Place on top of the moist cake topping and allow to dry.