Preheat your mini waffle maker according to manufacturer's instructions.
In a mixing bowl, whisk together the flour, cocoa powder, sugar, baking powder, baking soda, and salt until well combined.
In another bowl, whisk together the egg, milk, vegetable oil or melted butter, and vanilla extract until smooth.
Pour the wet ingredients into the dry ingredients and stir until just combined. Be careful not to overmix; a few lumps are okay.
Lightly grease the waffle maker with cooking spray or oil.
Spoon the batter onto the preheated waffle maker, using about 1-2 tablespoons of batter per mini waffle, depending on the size of your waffle maker.
Close the waffle maker and cook the mini waffles according to the manufacturer's instructions, typically for 3-5 minutes or until the waffles are cooked through and crispy on the outside.
Carefully remove the cooked waffles from the waffle maker and repeat with the remaining batter.
Serve the Chocolate Mini Waffles warm, topped with your favorite toppings such as fresh berries, whipped cream, chocolate sauce, or maple syrup.
Enjoy your delicious homemade Chocolate Mini Waffles as a delightful breakfast, snack, or dessert treat!