In a large pot, bring the water to a boil. Add the salt and sugar (if using).
Gradually stir in the maize meal, whisking continuously to prevent lumps.
Reduce the heat to low and cook the mixture, stirring frequently, for about 15-20 minutes, or until it thickens and the maize meal is fully cooked.
If desired, stir in the butter for added richness.
Transfer the Incwancwa to a serving dish or mold. Let it cool slightly before slicing or serving.
Enjoy your meal!