Bring 4 cups of water to a boil on the stove. Be sure to do this in a pot that can also be transferred to the oven with a lid.
Put 2 cups of cassava flour in a bowl and wet with cold water until it is just damp. Mix to incorporate.
When the water is boiling, add the pre-mixed flour and water into the boiling water, and whisk to combine. Continue to whisk until all of the lumps are out of the mixture.
Cover with a lid and place in oven for about 45 minutes.
Traditional Method
Bring 4 cups of water to a boil on the stove.
When the water is boiling, remove the pot from the stove. Sit on the ground with the pot in your lap (pro tip: put a beach towel over your lap, wear shoes, and have oven mitts handy). I did not splatter at all, but its better to be safe than sorry!
Pour the cassava flour into the water and whisk as fast and as hard as you can with a wooden oar (or a wooden spoon) until the mixture is completely smooth. A lumpy funje is considered subpar.
Enjoy right away!
Notes
Methods extracted from https://ethnicfoodsrus.com/around-the-world-recipes/african-cuisine/angolan-cuisine/funje/