In a small bowl, combine milk and vinegar and let it stand for around 5 minutes to “sour”.
In a separate bowl, combine flour, sugar, oats, baking powder, baking soda and salt.
Whisk vanilla extract, egg and olive oil 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.