In a large bowl, mix the cornmeal and cassava flour together.
In a large pot, bring 4 cups of water to a boil.
Gradually add the cornmeal and cassava flour mixture to the boiling water, stirring continuously to prevent lumps.
Reduce the heat to medium-low and continue stirring frequently for about 10-15 minutes, or until the mixture thickens and becomes smooth.
Reduce the heat to low, cover the pot, and let the mixture simmer for an additional 10-15 minutes, stirring occasionally. The banku should have a smooth, dough-like consistency.
Stir in the salt to taste.
Remove from heat and let it cool slightly before serving.
Enjoy your meal!