Preheat the oven to 180°C. Arrange the peppers and tomatoes, skin-sides down, on a roasting tray. Drizzle with 15ml olive oil and roast for about 15 minutes. Place the garlic, cheese, pine nuts, cashews and vinegar in a food processor and blend together gently. Add the roasted peppers, tomatoes and basil (if using) and blend at low speed. With the processor running, slowly add 100ml olive oil in a steady stream. (Depending on the thickness you require, you can adjust the amount of olive oil.) Season to taste and finish off with a squeeze of lemon juice. Place in an airtight container or sterilized glass jar – the pesto should keep for over two weeks in the fridge.
From Café Food at Home, by Evan Faull, courtesy Quivertree Publications.