Combine melted butter, melted chocolate, and granulated sugar in a bowl and mix well.

Add the eggs and mix well. The mixture may look curdled.

Add the flour and baking powder and mix until they are both well incorporated. The dough will be runny and look like a thin cake batter.

Place the dough into a bowl, cover with plastic wrap, and place into a refrigerator for at least 3 hours and up to overnight. The dough will stiffen after 3 hours.

Preheat an oven to 350⁰F.

Remove dough from the refrigerator and remove the plastic wrap.

Scoop dough into 1-inch balls and roll in granulated sugar, if using, then powdered sugar and place onto a cookie sheet, leaving at least 2 inches between cookie balls.

Place cookies into the preheated oven and bake for 10 to 12 minutes or until the edges bounce back when touched lightly. The middles may still look slightly wet, this will give you soft centers with crispy edges. Longer baking time will give you a firmer cookie.

Allow the cookies to cool for one minute before removing to a cooling rack. If cookies are allowed to sit on the baking sheet for more than 2 minutes they will stick to the cookie sheet.