Cut the capsicums into 3 cm (1¼ inch) squares. Peel and trim the fat from the kidneys, cut them into pieces the same size as the pieces of capsicum. Cut up the heart in the same way. Peel the calf’s liver and cut up in the same way.
For the marinade, combine the port with the olive oil and brown sugar. Add the meats, mix well.
Assemble the skewers, alternating the meats and diff