Please don't mind the change of name, the Nigerians call it Agidi but it is same as kafa.
Mix the corn starch/flour with the 700 mls of cold water in a pot. Please add water bit by bit because that's the best way to get a good mixture without lumps. If you are using Akamu or Ogi,
Place the pot on the stove and set the heating to medium low.
Stir continuously with a wooden spatula. You don't have to stir in one direction. Just make sure you are constantly stirring the mixture.
After some time, you will notice the corn starch mixture begin to thicken. Continue stirring because if you stop, lumps will form and you do not want that. If you are stirring continously and lumps are still forming, it means the heat is too much so reduce the heat.
When it has completely thickened like Custard, pour some water to the sides of the Agidi, cover the pot and leave to simmer for about 10 minutes on medium heat.
Stir well to mix the Agidi with the water.
To check that the Agidi is done, put a small quantity into some cold water. If it sets after cooling down then the Agidi is done.
Transfer to containers and leave to cool down completely at room temperature.
Read more at http://www.allnigerianrecipes.com/breakfast-recipes/agidi-eko.html#hF0u1MWl3y2XrSyx.99