Mix the liquids and sugar: In a large bowl, whisk together eggs, milks, vanilla extract, sugar and salt until well combined.
Add dry ingredients: Add flour, cocoa powder. Whisk again until smooth.
Add butter. Pour in the melted butter and whisk until fully incorporated.
Strain the batter. Pour the batter though a fine mesh strainer in to a clean bowl to remove any lumps. If there is too many lumps, rub them into the mesh with a spoon, so the get through the mesh.
Rest: Let the crepe batter rest at room temperature for 15-20 minutes. Otherwise, crepes might break during the flipping process.
Pour and swirl: Lightly grease 8-inch non-stick skillet with oil or butter over medium heat. Pour about half ladle (¼ cup) of batter into the hot skillet while tilting and swirling the pan to spread the batter into a thin, even circle.
Cook: Cook for 1 minute over medium heat. Using a wide spatula (non metal), lift off the edges around the crepe and carefully flip it. Cook it on other side for another 30-45 seconds. Repeat the process with the rest of the batter. You will have about 13-15 crepes using 8-inch skillet or about 12 crepes using 10-inch skillet.
Stack: Stack cooked crepes on a plate. Cover with a second plate while cooling if you prefer soft edges.
Serve: Serve with your favorite spreads, sauces, fresh fruit, nut butters or simply dust the with sugar.