Heat a skillet to medium heat.
In a mixing bowl or blender, add the flour, cocoa powder, sugar, and salt together. Mix until well combined.
Add in the eggs and mix until the mixture forms a paste (this will take roughly 30 seconds in a blender).
In a small bowl, whisk together the milk, vanilla, and butter.
Add the milk mixture to the flour mixture and mix well. If using a blender, this should take about 30 - 45 seconds. If you are mixing by hand, I recommend slowly adding in the milk mixture, whisking very well as you continue to add the milk.
Leave the batter to rest for about 10 minutes.
Pour 1/4 cup of the batter into your skillet and swirl until there is an even coating of the batter on the bottom of the skillet. Cook for a minute, then flip and cook for an additional minute.
Leave the cooked crepe on a wire rack in a warm oven while you cook the remaining crepes.
Serve with fruit, whipped cream, caramel, or any other toppings and fillings you desire.