1. Preheat your oven to 150°C.
2. First mix 150 gr of flour (yes, you read that right, the rest you'll have to put in later), the sugar, the yeast, the pinch of salt.
3. Mash 2 bananas, mix with the butter and milk. Add this to the mixture. Meanwhile, melt the chocolate in a bain-marie. Then add the eggs, the Morand chocolate syrup, the melted chocolate and the rest of the flour to your mixture. Mix everything together until you have a smooth dough.
4. Grease the marbled pan and pour in the dough. Cut the remaining banana(s) in half lengthwise and place both halves on the pastry, inside up. Bake the mixture in the oven for 50 to 60 minutes, checking that it is cooked through.