In a large mixing bowl, whisk together the flour, sugar, baking powder, baking soda, and salt.

In a separate bowl, whisk together the buttermilk, milk, egg, melted butter, and vanilla extract.

Pour the wet ingredients into the dry ingredients and gently stir until just combined. Do not overmix; it's okay if there are a few lumps.

Heat a non-stick skillet or griddle over medium heat and add a small amount of butter or oil to coat the surface.

Using a 1/4 cup measuring cup, pour the batter onto the skillet or griddle. Cook until bubbles form on the surface of the pancake, then flip and cook for another 1-2 minutes until golden brown.

Repeat with the remaining batter, adding more butter or oil as needed.

Serve the pancakes warm with maple syrup.