Roasted vegetable soup with walnut and sage pesto

Method

1. Preheat the oven to 200°C/fan180°C/gas 6. Put the vegetables in a large, non-stick roasting tin with 20 squirts of oil (or 2 tablespoons). Sprinkle with pepper, toss well, and roast in the oven for 45 minutes.
2. Meanwhile, make the pesto. Put the nuts, garlic, sage and parsley into a mini food processor and blend until finely chopped. Transfer to a bowl and stir in the oil, 3 tablespoons hot water, breadcrumbs and Parmesan. Set aside.
3. Transfer the vegetables from the oven to a pan. Add 1.5 litres cold water and bring to a simmer. Cover and cook for 20 minutes.
4. Leave the soup to cool slightly, then whizz in a food processor or with a hand-held blender. Return to the pan and reheat gently, if necessary. Season, ladle into warm bowls, swirl in a little pesto and serve.