Put tea in a small pot. Pour 150 ml of boiling water and simmer covered for about 20 minutes. Let it cool down. Roast the hazelnuts and almonds separately in a pan without fat, remove. Let cool off. Chop hazelnuts coarsely.
Set aside 2 tbsp. hazelnuts for garnishing. Cream fat, vanilla sugar, sugar, cinnamon and salt with the whisk of the hand mixer. Stir in the eggs one by one. Mix flour, almonds and baking powder and stir in alternately with the tea. Peel banana and cut into small pieces. Fold in hazelnuts and banana pieces. Pour the dough into a greased, flour-spread box form (30 cm long). Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 1 hour on the lower shelf (stick test). Remove the cake from the oven and let it cool down for about 15 minutes. Turn out of the tin onto a cake rack and allow to cool. Coarsely chop the chocolate coating.
Pour the dough into a greased, flour-spread box form (30 cm long). Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 1 hour on the lower shelf (stick test). Remove the cake from the oven and let it cool down for about 15 minutes. Turn out of the tin onto a cake rack and allow to cool. Coarsely chop the chocolate coating. Melt the couverture and coconut oil in a bowl over a warm water bath. Pour the couverture onto the cake surface. Chill the cake for approx. 10 minutes, then spread the remaining nuts on the cake and chill for approx. 50 minutes until the chocolate is firm
waiting time 3 hours