Beat eggs with sugar until creamy. Fold in hazelnuts and bitter almond oil. Spread the dough evenly on a tray lined with parchment paper and bake at 150 °C -160 °C on the top shelf in an unheated oven.
After baking, turn the cake out onto a table sprinkled with sugar and carefully remove the paper. Cut the base into 4 pieces.
For the filling, whip the cream until stiff, stir in the cocoa, coffee powder and sugar. Spread the filling on the bottoms and place them on top of each other. Use the rest of the cream for the sides. Use a fork to draw patterns through the top layer. Divide the cake into pieces, each cutting off as much as they like on any side.