Chef Hubert Keller mixes green, white, pink and black peppercorns with coriander seeds and crushes them. He brushes oblong ground beef patties with Dijon mustard and then presses the spice mixture onto both sides. He cooks the burgers in olive oil, removes them, drains the fat and deglazes the pan with red wine and cognac. He reduces it almost completely and then adds chicken stock, reduces it by half, adds cream and simmers. He finishes it with mustard.
He moistens the bun with the sa