Combine buttermilk, egg, butter, and vanilla extract in medium bowl or large measuring cup with a pour spout. Whisk until well combined.
Whisk flour, sugar, baking powder, baking soda, and salt in a medium bowl to combine.
Add the wet ingredients to the flour mixture and whisk very gently to start combining the ingredients. Add chocolate chips and fold them in with a spatula, taking care not to over-mix the batter.
Using a 1/4 cup measure, add batter to a lightly greased griddle or skillet preheated to medium-high. Cook pancakes until large bubbles begin to appear on the top surface, about 1 1/2 to 2 minutes. Flip pancakes with a thin, wide spatula and cook until golden brown on the second side, about 1 to 1 1/2 minutes more. Serve immediately or keep pancakes warm in an oven heated to 200º F until ready to serve.