Start by heating the oven to 200°C. Lay the aubergine, pepper, tomatoes and onion in a single layer on a baking sheet. Mix with the 4 tablespoon of oil and a good sprinkling of salt and pepper. Roast for 30 minutes.
Fry the garlic and chilli in a little more oil over a medium heat until slightly softened. Add the capers, red wine vinegar, olives and roasted vegetables to the pan and mix everything together heating gently through for a couple of minutes.
Mix the cooked orzo and vegetable mixture together in a large bowl and top with fresh parsley and another drizzle of olive oil if required.