In a large mixing bowl, combine 250 grams of all-purpose flour, 50 grams of cocoa powder, 2 teaspoons of baking powder, 1/2 teaspoon of baking soda, and a pinch of salt. Mix well.
In another bowl, whisk together 2 large eggs, 100 grams of granulated sugar, 120 ml of milk, 120 ml of buttermilk, 60 ml of vegetable oil, and 1 teaspoon of vanilla extract.
Gradually pour the wet ingredients into the dry ingredients, mixing until a smooth batter is formed. Let the batter rest for 10 minutes.
Preheat your waffle iron and lightly grease it with oil or butter.
Pour the appropriate amount of batter (as per your waffle iron's instructions) onto the preheated waffle iron and cook until the waffles are crispy and cooked through, usually 4-5 minutes.
Carefully remove the waffles from the iron and serve immediately with your choice of toppings, such as whipped cream, chocolate syrup, or fresh fruits.