Place 2 cups whole milk, 2 tablespoons packed light brown sugar, and 1 teaspoon kosher salt in a medium saucepan. Cook over medium-low heat until bubbles begin to form around the edges of the pan. Add 3/4 cup finely ground cornmeal and whisk to combine. Cook, whisking often, until creamy and thickened, about 3 minutes. Remove from the heat.