Preheat oven to 375° F.
Melt butter and chocolate in two microwave-safe bowls or together using a double boiler and stirring every 30 seconds. Once melted, set each aside to cool (you may refrigerate the bowls for a few minutes to accelerate cooling but don’t let the butter or chocolate set again).
In a large bowl, stir to combine sugar, eggs and vanilla. Add the melted butter and melted chocolate – whisk together until smooth.
In a separate bowl, whisk together gfJules Flour, baking powder and baking soda. Slowly stir into chocolate bowl to mix. The dough will become too thick for a whisk, so switch to a wooden spoon or use the paddle attachment on a stand mixer.
Cover and refrigerate dough or bake right away.
Line baking sheets with parchment paper.
Scoop dough into 1-inch balls, rolling between your palms to smooth, then rolling in powdered sugar to coat all over -- the dough will be thick and very sticky.
Place each on lined baking trays, leaving 1 ½ inches between them to allow for some spread.
Bake for 9-10 minutes or until the cracks do not look shiny and wet.
Remove to cool on wire racks.