Bring water to a boil in a large pot. Add sea salt.
Take cornmeal by the handful and add to water slowly by sprinkling it bit by bit. Stir quickly to avoid lumps. Use a long handled wooden spoon (I used one with a hole in the middle which is more suitable for liquid consistency meals).
Cook for 20-30 minutes, stirring constantly. Polenta will become very thick while cooking. It is done when it comes away cleanly from the sides of the pot.
Optional - Add butter.
Pour polenta in a round shape form and let it cool for 15 minutes.