There's nothing like fresh blueberry pancakes to start an autumn day.  My personal favorite is blueberry buttermilk pancakes.  Here, I used frozen blueberries.  I generally find frozen berries to be pretty bland..and unfit for everyday eating.  I imagine that they are the ugly ducklings of the blueberry world, shoved into plastic bags and thrown into the freezer.  Cooking the blueberries with a splash of balsamic vinegar and pinch of sugar, however, turns these little guys in to the swans of the frozen fruit world.