In a large bowl, whisk together the flour, cocoa powder, sugar, baking powder, and salt until evenly combined.
In a separate bowl, beat the egg and then whisk in the milk, melted butter (or oil), and vanilla until smooth.
Pour the wet ingredients into the dry ingredients and stir gently until just combined; small lumps are fine—do not overmix.
Fold in chocolate chips if using, taking care not to overwork the batter to keep pancakes tender.
Heat a nonstick skillet or griddle over medium heat and lightly grease with butter or oil.
Drop about 1/4 cup of batter per pancake onto the hot surface, spacing them evenly.
Cook until edges set and small bubbles appear on top, about 1½–2 minutes.
Flip carefully and cook the second side until set and slightly springy, about 1–2 minutes more.
Transfer cooked pancakes to a warm plate and keep loosely covered while you finish the remaining batter.
Serve stacked with a drizzle of chocolate sauce or maple syrup, a pat of butter, and optional fruit or powdered sugar.