Preheat oven to 350. Grease 8" skillet and set aside.
In a medium bowl stir together pancake mix, buttermilk, vanilla, and cinnamon until combined. Batter will still be lumpy but that's ok. Fold in blueberries. Pour batter into the prepared skillet and bake at 350 until for about 30 minutes or until the top is golden brown and a toothpick inserted into the middle of the pancake comes out clean.