Place the melted butter, 1 1/4 cups all-purpose flour, 3/4 cup finely ground yellow cornmeal, 1/2 cup whole buttermilk, 2 large eggs, 2 tablespoons packed light brown sugar, 2 teaspoons vanilla extract, 2 teaspoons baking soda, 1 teaspoon baking powder, and 3/4 teaspoon kosher salt in a large bowl and whisk until combined; the batter will be quite thick.
