In a medium bowl, combine the milk and the vinegar, and let stand for at least 5 minutes to "sour"
In a separate bowl, combine flour, sugar, baking powder, baking soda and salt in a large mixing bowl. Whisk egg and butter into the “soured” milk. Pour the flour mixture into the wet ingredients, and whisk it together until the batter is smooth.
Heat a large skillet over medium heat and spray with cooking spray. Scoop 1/4 cup of batter for each pancake, and flip when bubbles are covering the surface of the pancake. Flip and cook the other side until it is golden.