For the blueberry syrup: In a saucepan, combine the blueberries, sugar and 1/2 cup water. Bring to a gentle boil and cook for 5 minutes on low. Stir in the cornstarch, then continue to cook, using a whisk or spoon to mash the larger pieces of blueberries. Remove from the heat when the syrup is nice and thick.
For the cornmeal pancakes: Mix together the cornmeal, flour, sugar, baking powder and salt in a bowl. In a separate bowl, mix the milk, vinegar, vanilla and eggs. Pour the milk mixture into the dry ingredients, stirring gently. Stir in the melted butter. If the batter is overly thick, splash in a small amount of milk.
Heat 1 tablespoon melted butter in a skillet over medium-low heat. When hot, drop in 1/4 cup batter per pancake and cook until golden brown on both sides, about 2 minutes per side. Remove from the skillet and keep warm. Continue with the remaining batter, using more melted butter as needed
Stack some pancakes for each serving, placing a pat of butter on top. Drizzle with warm maple syrup if desired, then spoon blueberry syrup over the top. Dig in!