1In a bowl, heat butter and brown sugar in microwave.Keep it aside.
2In another bowl,melt the chocolate.
3Pre heat the oven at 150 degrees C with top and bottom rods on. Line a rectangular tin with parchment sheet or aluminium foil.
4In a bowl, using hand mixer , beat the eggs for two minutes on medium speed.
5Add melted butter and sugar. Continue beating.
6Now using a spatula, gently fold in flour and cocoa powder.
7Do not stir. Fold in mashed banana.
8Now fold in melted chocolate.
9Transfer the batter into the prepared tin.
10Bake for 25 minutes at 150 degrees C with top and bottom rods on.
11Now take the tin out and place banana slices.
12Brush the slices with melted butter
13Place it back in the oven and bake for 8-10 mins with the top rod alone on.
14Transfer it to a wire rack .Allow it to cool.