Preheat the oven to 180C/350F/Gas 4.
For the poussin, heat the olive oil in an ovenproof pan and add the poussin and garlic. Fry the poussin for 4-6 minutes, turning frequently, or until golden-brown all over. Season well with salt and freshly ground black pepper, then transfer to the oven to roast for 12-15 minutes, or until cooked through.
For the peppers, heat the olive oil in a frying pan and add the peppers and olives. Fry for 6-7 minutes, or until the peppers are tender.
For the sauce vierge, gently heat the oil, lemon juice and garlic in a small pan until warmed through. Remove from the heat and stir in the basil.
To serve, place the poussin and peppers onto a serving dish and drizzle over the sauce vierge.