Combine milk with vinegar in a medium bowl and set aside for 5 minutes to "sour".
Sift flour, sugar, baking powder, baking soda, cinnamon and salt in a large mixing bowl. Add blueberries and mix to coat. Whisk egg, vanilla and butter into "soured" milk. Pour the wet ingredients into flour mixture and stir until just blended. Heat a large skillet over medium heat, and coat with cooking spray. Pour 1/4 cupfuls of batter onto the skillet, and cook until bubbles appear on the surface. Flip with a spatula, and cook until browned on the other side.