Preheat the oven to 180C (fan). In a food processor, blend the beans, dates and oil together to a smooth paste. Add the other ingredients and blend until everything is well incorporated.

Pour into a 20cm cake tin lined with baking paper and use a palette knife or spoon to smooth the top. Bake for 45 minutes in the centre of the oven or until a skewer comes out clean.

Leave to cool on a wire rack before placing carefully on a serving plate (it breaks easily).

To make the icing, scoop the avocados out of their skin and blend in a food processor with the other icing ingredients. Adjust the syrup to taste. Use a palette knife to spread over the top of the cake.

The cake will keep in an airtight container for several days