In a large pot, bring the water to a boil. Add the salt.
Gradually whisk in the cornmeal, stirring constantly to prevent lumps.
Reduce the heat to low and continue to cook, stirring frequently, for about 30-40 minutes, or until the mixture thickens and the cornmeal is tender. The polenta should pull away from the sides of the pot when done.
Stir in the butter and grated cheese if using. Mix until the butter is melted and the cheese is well incorporated.
Remove from heat and let it sit for a few minutes to firm up slightly.
Spoon the mămăligă onto a serving plate. You can also pour it into a greased dish and allow it to cool before slicing into squares.
Garnish with fresh herbs if desired.
Enjoy your meal!