I saw Nadja Hussein cook with banana skins and tried it the next day. Not only do they taste good, they are a huge source of goodness (specifically potassium) and you are not then wasting them.
Skins of 2-4 bananas
2-3 spring onions
1 clove garlic
1 tblsp dark (or other) miso paste
1 tblsp olive or other oil
Start cooking the polenta according to the instructions.
Chop away the very tips of the banana skins and discard them. Using a fork or knife slice the skins into thin strips. Using the fork is easier. Just place the skins on a board and pull at them with the upside of the fork turned down.
Heat the oil in a non-stick pan and fry the skins with the onions and garlic. Make a paste with the miso, mustard and as much water as you need for the consistency you want. Add that to the pan and let it all simmer for about 5 to 10 minutes before serving with polenta.