In a 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 pan over medium heat. Pour ¼ cup of batter onto the pan for each pancake. Cook until bubbles form on the surface, then flip and cook until the other side is golden brown.