Whisk 1 cup of non-instant polenta cornmeal, 4 cups of cold water, and 1 teaspoon of fine salt in a saucepan.
Bring to a simmer over medium-high heat, stirring. Reduce to low and cook for about 45 minutes, stirring frequently, until thick and the grains are tender.
Remove from the heat. Stir in 3 tablespoons of unsalted butter and ½ cup of grated Parmesan until melted. Serve immediately.
