Place butter in a small sauce pan and heat on medium until melted. Then, continue to heat until there are no more bubbles coming up and the whistling has reduced (about 5min). Pass your brown butter through the sift. Set aside.
Place milk in a medium sauce pan and heat on low until lukewarm. Set aside.
In a mixing bowl, whisk the eggs and egg yolks together. Add the warm milk. Incorporate in 2-3 times the all-purpose flour, powdered sugar and unsweetened cocoa powder. Finally add the cooled melted butter. Mix until your batter is smooth.
REST
Cover your batter with a plastic wrap and leave it at room temperature for about 1 hour.
COOK!
Heat your Pancake pan on Medium 5 minutes prior starting making your "Crêpes" and slightly oil the surface with a kitchen towel.
Pour one large scoop of batter in your pan, spreading it over with your spatula.
Once one side is cooked, flip it over. Cook it for a few seconds more. NOTE: Chocolate crêpes need a bit more of cooking time than regular ones. Then, serve. Enjoy & Bon Appétit!