Combine Dry Ingredients: In a medium bowl, whisk or stir together the cocoa powder, all-purpose flour, sugar, baking powder, and salt until evenly combined; set the mixture aside.
Mash the Banana: In a large bowl, mash the banana thoroughly with a fork.
Mix Wet Ingredients: Add the milk, eggs, melted butter, and vanilla extract to the mashed banana; use the fork to break up the eggs first, then mix the ingredients together with the liquids.
Combine the Batter: Add the dry mixture to the bowl of wet ingredients and stir just until the flour is incorporated; do not be concerned about some visible lumps, as these may be pieces of mashed banana.
Heat the Cooking Surface: Place a non-stick griddle or large pan over medium-high heat and allow it to become hot; if using an electric griddle, set it between 300°F and 350°F.
Grease the Surface: Once the cooking surface is hot, grease it with cooking spray, butter, or another suitable amount of butter.
Portion the Batter: Immediately pour ¼ cup of batter onto the greased cooking surface for each pancake.
Cook the First Side: Cook each pancake for about 2 minutes, watching for the edges to become defined and bubbles to appear on the surface.
Flip the Pancakes: Turn the pancakes over once the edges are set and bubbles have formed, then cook the second side for about 1 minute.
Avoid Pressing: Do not press down on the pancakes after flipping, as this can make them denser and chewier and may cause uncooked batter to ooze from the sides.
Keep Pancakes Warm: Transfer each finished pancake to a plate and keep the cooked pancakes warm while you continue cooking the remaining batter.
Serve: Arrange several warm pancakes on a plate and finish with your favorite toppings and syrups.
