In a large, heavy stew pot, boil the palm oil for 10 minutes. Add onions and pepper and continue cooking on high heat for another 5 minutes.

Reduce heat, add remaining ingredients and simmer for an hour or more, until soup is somewhat thickened. 

Ghana Fufu is made mainly with Plantain and a bit added Cassava.  Stir from time to time. If there is too much palm oil on the surface for your liking, skim it off with a large spoon before serving. 
If you like an more real Ghana taste, visit on of your local African shops, and ask for FuFu! They are happy to help you out!