Into a medium bowl, add milk and vinegar. Mix well and set aside to thicken for 5 minutes. Whisk oil and vanilla into the milk mixture.

Into a large bowl, add flour, baking soda, baking powder, salt, and sugar, and combine. Add milk mixture to the flour mixture and whisk until the batter is just combined, being careful not to overmix.

Heat a frying pan over medium-high heat and spray with non-stick cooking spray. Ladle ¼ cup of the batter into pan and sprinkle on chocolate chips or fruit (if using). When bubbles begin to set around edges of pancake, after approximately 2 minutes, flip and cook 2 to 3 minutes on the other side. Repeat process with remaining batter and serve immediately.