In a blender, combine the broth, peanut butter, honey, onion, garlic, soy sauce, gravy base and pepper. Put the ham in a shallow glass dish, pour the marinade over it, and marinate for 3 to 4 hours in the refrigerator.
Prepare a charcoal fire. Remove ham from marinade and cook approximately 15 minutes per side over glowing coals. Carve into 1-inch thick slices.