Pour 2 cups of whole milk and 4 tablespoons of butter into a medium saucepan and heat over medium heat, stirring occasionally, until the butter melts and the milk is steaming, about 5 minutes.

While whisking constantly, slowly whisk in 1/2 cup cornmeal into the hot milk mixture to prevent lumps.

Continue cooking over medium heat, stirring frequently, until the mixture thickens and begins to pull away from the sides of the pan, about 2 to 3 minutes.

Remove the pan from heat and stir in 1 teaspoon salt, 1/4 teaspoon black pepper, and 1 tablespoon sugar if using; let the mixture cool for 5 minutes.

Separate 4 large eggs, placing yolks in one bowl and whites in another; beat the egg whites in a clean bowl with an electric mixer until stiff peaks form.

Whisk the egg yolks into the cooled cornmeal mixture one at a time, then stir in 1 teaspoon baking powder until fully incorporated.

Gently fold the whipped egg whites into the cornmeal batter in two batches, using broad, sweeping motions to preserve the air bubbles.

Preheat the oven to 350°F and butter an 8 by 8 inch or 9 inch round baking dish; pour the batter into the dish and bake for 30 to 35 minutes until the top is golden brown and the center jiggles slightly.