- Preheat the oven to 160 C and line a loaf tin with baking paper
- Place the dates in a saucepan with the boiling water and simmer for 20 minutes
- Drain the liquid into a jug and set to one side.
- Put the dates into a food processor, alongside the bananas and 100ml of date liquid and whizz until smooth.
- Mix the nuts, dried fruit, polenta, cinnamon and baking powder in a bowl.
- Add the date puree and stir until combined.
- Whisk the egg whites to soft peaks and fold into the cake mix.
- Tip the mixture into the tin and bake for 1 hour.
- Leave to stand for 10 minutes in the tin and wait until completely cool before cutting into slices