In a large bowl, whisk together the flour, cocoa powder, baking powder, salt, and sugar until evenly combined.

In a separate bowl, mix the milk, egg, and melted butter until smooth and well-blended.

Pour the wet ingredients into the dry mixture, stirring gently until just combined. The batter should be slightly lumpy; avoid overmixing.

Preheat a non-stick skillet or griddle over medium heat and lightly grease it with cooking spray or a little butter.

Pour about 1/4 cup of batter onto the skillet for each pancake. Cook for 2-3 minutes or until bubbles form on the surface and the edges look set.

Flip the pancakes carefully and cook for an additional 2 minutes, or until they are puffed and lightly browned.

Remove the pancakes from the skillet and keep warm in a low oven as you cook the remaining batter.

Drizzle with chocolate sauce just before serving.