In small bowl, mix together vinegar and milk of your choice. Let sit while preparing dry ingredients(Omit this step if using buttermilk.)
Sift or whisk together flour, baking soda, baking powder and salt.
Add peanut butter, egg, and vanilla to milk mixture and mix until well incorporated. Add this mixture to dry ingredients and milk until just combined. Feel free to add in 1 tablespoon additional milk if you feel the pancake batter is too thick.
Preheat a griddle or non-stick pan over medium heat. Spray or grease pan with butter.
Once pan is heated, ladle pancake batter unto pan, using 1/4 cup measuring cup.
Cook pancakes until bubbles form on top of surface and then carefully flip. Cook for another 1-2 minutes and remove from pan.