Mix sieved plantain flour and overripe plantains into a bowl, add a small amount of warm water and blend to form a thick smooth paste.
Add the crayfish (optional) onions and chillies and mix together. Blend in the palm oil and stock cubes and season well. Add extra warm water or flour if too stiff or soft, the mixture should be stirrable.
Scoop the mixture into small parcels in sealed aluminium containers or banana leaves and seal well with foil. Add to a pan of simmering water and cook for 35 minutes until a knife comes out clean.
Leave to cool and set and serve alongside porridge, custard or a cold drink.