Preheat the oven to 180 ° C (approx. 200 ° C top / bottom heat).
Mash or puree the bananas and mix in the kitchen machine with all the other ingredients except the nuts and chocolate. Chop the walnuts and chocolate and fold into the batter. Grease a loaf pan, pour in the dough and smooth it out.
Bake the cake for about 40 minutes. If necessary, cover with aluminum foil for the last 15 minutes, as it gets dark very easily. Make a chopstick sample.