In a large bowl, whisk together the flour, sugar, baking powder, baking soda, and salt.
In a medium bowl, whisk the buttermilk, melted butter, eggs, and vanilla extract together.
Pour the liquid ingredients over the dry ingredients and mix until just combined. The batter will be lumpy and that is ok. Gently fold in the chocolate chips. You don’t want to over mix the batter. Let the batter sit for 5 minutes.
Heat a griddle or large skillet over medium-high heat. Add a pat of butter to the griddle or skillet and spread it around until melted.
Using a ¼ cup measuring cup, spoon the batter onto the hot griddle or skillet. Cook until small bubbles form all across the top of the pancakes, about 3 minutes, then flip and continue to cook until golden brown. Repeat with remaining batter.
Serve pancakes warm with butter and maple syrup, if desired.
To keep pancakes warm, place in a single layer on a large baking sheet and place in a 200°F oven.