Cook the pepper under a preheated hot grill until the skin blackens. Remove and cover with damp kitchen paper until it is cool enough to handle, then peel and chop.
Blend together the garlic, olives, 1 teaspoon oil, the capers and the chopped red pepper.
Put the shallots and the remaining oil in a small pan. Cover and cook, stirring frequently, over low heat for 15 minutes. Add the vinegar and sugar and cook uncovered, stirring frequently, for a further 5 minutes.
Season the steaks and cook, 2 at a time, in a preheated heavy-based frying pan or griddle pan. Cook on one side, then transfer to a baking sheet. Top each steak with some red pepper mix. Bake in a preheated oven, 200°C (400°F), Gas Mark 6, for 5 minutes or according to taste. Leave to stand in a warm place for 5 minutes before serving with the balsamic shallots and, if liked, steamed wholegrain rice.