Cornmeal Pancakes with Blueberry Syrup

Name: Cornmeal Pancakes with Blueberry Syrup
Ingredients: 1 pint blueberries; 1 cup sugar; 2 tablespoons cornstarch; 1 1/2 heaping cups yellow cornmeal; 1 1/2 cups all-purpose flour; 1/4 cup sugar; 2 tablespoons baking powder; 1/2 teaspoon kosher salt; 2 1/4 cups whole milk, plus more for thinning if needed; 1 tablespoon white vinegar; 1 tablespoon vanilla; 2 large eggs; 4 tablespoons salted butter, melted, plus additional melted butter for the skillet; Pats of butter, for serving; Maple syrup, for serving, optional