Sift the cocoa powder to prevent clumping. Salt isn’t used in this recipe to better control the salt content. Make sure the ground beef is cold, straight from the fridge, to prevent the fat from emulsifying with the meat. If you don’t own a ring mold, a mayonnaise lid could be used as a substitute. We prefer cooking our burgers on a flat surface such as a flat top or a frying pan for a hard sear.