- Season the Chateaubriand lightly with kosher salt, and then rub the Dijon all over the beef. Set aside.
- Mix together the espresso, brown sugar, kosher salt, cocoa powder and black pepper.
- Roll the Chateaubriand in the spice mixture.
- Grill the beef over a moderate flame until desired doneness is achieved. 130 degrees, internal temperature for medium rare.
- While the Beef is grilling, or beforehand, mix the butter with the lemon juice, cocoa powder, sugar and salt.
- After the beef is cooked and rested, slice and serve with the cocoa compound butter.