Place half of the water in a medium-size saucepan, add the salt, and bring it to a boil over medium heat.

Slowly mix the cornmeal into the remaining water.

Gradually pour that mixture into the boiling water, stirring constantly. Add the butter and continue to stir constantly until the angu turns into a thick porridge which will hold its shape. Pour the angu into a well-buttered 6-cup mold. Let cool, then unmold.