In a large mixing bowl, whisk together the flour, cocoa powder, sugar, baking powder, baking soda, and salt.
In another bowl, whisk together the milk, egg, melted butter, and vanilla extract.
Pour the wet ingredients into the dry ingredients and stir until just combined. Do not overmix.
Heat a non-stick skillet over medium heat. Pour ¼ cup of batter onto the skillet for each pancake. Cook until bubbles form on the surface, then flip and cook until browned on the other side.