Crumble the yeast, stir with sugar until liquid. Melt butter in a pot, add milk, remove from heat. Put salt and flour in a bowl. Peel the banana, mash 1 egg with the banana, add. Add milk mixture and yeast as well, immediately knead to a smooth dough with the dough hooks of the hand mixer. Cover the dough and let it rise in a warm place for about 45 minutes.
Knead the chocolate drops down to 1 tablespoon. Divide the dough into 3 equal pieces. Form into 3 strands (each approx. 55 cm long) on a floured work surface. Weave the strands into a braid. Lay diagonally on a baking tray lined with baking paper. Leave to rise again for another 25 minutes.
Whisk 1 egg and brush the plait with it. Sprinkle the rest of the chocolate drops on top. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for 25-30 minutes. Remove and let cool on a cake rack.