Combine milk with vinegar in a large bowl and set aside for 5 minutes to “sour.” In a medium mixing bowl, combine flour, sugar, baking powder, baking soda and salt. Whisk egg and butter into “soured” milk. Pour the flour mixture into the wet ingredients and whisk until lumps are gone. Heat a large, greased skillet over medium heat. Pour 1/4 cupfuls of batter onto the skillet, top with blueberries, and cook until bubbles appear on the surface. Flip with a spatula and cook until browned on the other side.