In a large pot, bring 4 cups of water to a boil.
Gradually add the cassava flour to the boiling water, stirring continuously to prevent lumps. If using plantain flour, add it at this stage.
Reduce the heat to low. Continue to stir the mixture until it thickens and becomes smooth. This should take about 10-15 minutes. The consistency should be thick and stretchy.
If desired, stir in palm oil or vegetable oil for added flavor.
Remove the pot from heat and let the Fufu sit for a few minutes to set.
Use a wooden spoon to transfer the Fufu to a serving dish. It should be smooth and pliable.
Enjoy your meal!