Add water and salt to a medium pot and bring to a steady boil. The water should be bubbling evenly, not just lightly simmering.
Slowly sprinkle in cornmeal while whisking constantly. This prevents lumps and keeps the texture smooth.
Keep stirring for 3–5 minutes until the mixture thickens and feels heavier. You will notice a mild, slightly nutty aroma.
Reduce heat to low and cook until the mixture pulls away from the sides of the pot. This shows the starch has fully absorbed the water.
Stir in butter if using, until fully melted and smooth. The mixture should look creamy and glossy.
For soft mamaliga, serve immediately while warm. For firm texture, continue cooking briefly and let it rest covered.
Pour into a dish or bowl and let it cool until set if you want sliceable polenta. It should hold its shape when cut.