Steps
1. Add flour gradually to mashed banana, beating well with a wooden spoon until all the flour is well mixed. Add half a cup warm water and salt.
2. Beat well and leave covered in a warm place to rise (3-4 hours).
3. Add oil and mix.
4. Add beaten egg, nutmeg and warm water.
5. Beat well and add baking powder.
6. Pour into a well-greased bread tin or small individual moulds and bake until cooked and brown. Test as for cake.
7. Turn out of mould and serve in slices, hot or cold.

Source
Food and Agriculture Organization of the United Nations (1991), Post-harvest and processing technologies of African staple foods: a technical compendium, ISBN 92-5-103076-6, Rome